From 9309df4196cbe1a30b7b8f7cc88dd67aac3c151c Mon Sep 17 00:00:00 2001
From: gorhill <rhill@raymondhill.net>
Date: Sun, 22 Jan 2017 16:05:16 -0500
Subject: [PATCH] 3rd-party filters pane revisited

---
 assets/assets.json              |  11 +-
 src/3p-filters.html             |  37 +++---
 src/css/3p-filters.css          | 131 ++++++++++++-------
 src/js/3p-filters.js            | 217 ++++++++++++++++++--------------
 src/js/assets.js                |  10 +-
 src/js/background.js            |   1 +
 src/js/messaging.js             |  22 ++--
 src/js/scriptlets/subscriber.js |  40 +-----
 src/js/storage.js               | 204 ++++++++++++++++++++----------
 src/js/ublock.js                |   3 -
 10 files changed, 394 insertions(+), 282 deletions(-)

diff --git a/assets/assets.json b/assets/assets.json
index 7b361c3cf..24bc1f473 100644
--- a/assets/assets.json
+++ b/assets/assets.json
@@ -30,7 +30,8 @@
 		"contentURL": [
 			"https://raw.githubusercontent.com/uBlockOrigin/uAssets/master/filters/filters.txt",
 			"assets/ublock/filters.txt"
-		]
+		],
+		"supportURL": "https://github.com/uBlockOrigin/uAssets/issues"
 	},
 	"ublock-badware": {
 		"content": "filters",
@@ -196,7 +197,11 @@
 		"group": "social",
 		"off": true,
 		"title": "Anti-ThirdpartySocial (see warning inside list)",
-		"contentURL": "https://www.fanboy.co.nz/fanboy-antifacebook.txt",
+		"contentURL": [
+			"https://easylist.to/easylist/fanboy-social.txt",
+			"https://fanboy.co.nz/fanboy-antifacebook.txt",
+			"https://easylist-downloads.adblockplus.org/fanboy-social.txt"
+		],
 		"supportURL": "https://forums.lanik.us/"
 	},
 	"fanboy-annoyance": {
@@ -206,6 +211,7 @@
 		"title": "Fanboy’s Annoyance List",
 		"contentURL": [
 			"https://easylist.to/easylist/fanboy-annoyance.txt",
+			"https://fanboy.co.nz/fanboy-annoyance.txt",
 			"https://easylist-downloads.adblockplus.org/fanboy-annoyance.txt"
 		],
 		"supportURL": "https://forums.lanik.us/"
@@ -217,6 +223,7 @@
 		"title": "Fanboy’s Social Blocking List",
 		"contentURL": [
 			"https://easylist.to/easylist/fanboy-social.txt",
+			"https://fanboy.co.nz/fanboy-social.txt",
 			"https://easylist-downloads.adblockplus.org/fanboy-social.txt"
 		],
 		"supportURL": "https://forums.lanik.us/"
diff --git a/src/3p-filters.html b/src/3p-filters.html
index 48086f71f..d35910399 100644
--- a/src/3p-filters.html
+++ b/src/3p-filters.html
@@ -21,24 +21,19 @@
             <button id="buttonPurgeAll" class="custom disabled" data-i18n="3pPurgeAll"></button>
         <li><input type="checkbox" id="parseCosmeticFilters"><label data-i18n="3pParseAllABPHideFiltersPrompt1" for="parseCosmeticFilters"></label><button class="whatisthis"></button>
             <div class="whatisthis-expandable para" data-i18n="3pParseAllABPHideFiltersInfo"></div>
-            <ul style="padding-left: 2em;">
-                <li><input type="checkbox" id="ignoreGenericCosmeticFilters"><label data-i18n="3pIgnoreGenericCosmeticFilters" for="ignoreGenericCosmeticFilters"></label><button class="whatisthis"></button>
-                <div class="whatisthis-expandable para" data-i18n="3pIgnoreGenericCosmeticFiltersInfo"></div>
-            </ul>
-        <li><p id="listsOfBlockedHostsPrompt"></p>
+        <li><input type="checkbox" id="ignoreGenericCosmeticFilters"><label data-i18n="3pIgnoreGenericCosmeticFilters" for="ignoreGenericCosmeticFilters"></label><button class="whatisthis"></button>
+            <div class="whatisthis-expandable para" data-i18n="3pIgnoreGenericCosmeticFiltersInfo"></div>
     </ul>
+    <p><span id="listsOfBlockedHostsPrompt"></span></p>
     <ul id="lists"></ul>
 </div>
 
 <div id="externalListsDiv">
-<p>
-    <span data-i18n="3pExternalListsHint" style="margin: 0 0 0.25em 0; font-size: 13px;"></span>
-    <a class="fa info" href="https://github.com/gorhill/uBlock/wiki/Filter-lists-from-around-the-web" target="_blank">&#xf05a;</a>
-    </p>
-<p style="margin: 0.25em 0 0 0">
-    <textarea id="externalLists" dir="ltr" spellcheck="false"></textarea>
-    <button id="externalListsApply" class="custom important" disabled="true" data-i18n="3pExternalListsApply"></button></p>
-</div>
+    <p>
+        <span data-i18n="3pExternalListsHint" style="margin: 0 0 0.25em 0; font-size: 13px;"></span>
+        <a class="fa info" href="https://github.com/gorhill/uBlock/wiki/Filter-lists-from-around-the-web" target="_blank">&#xf05a;</a>
+        <textarea id="externalLists" dir="ltr" spellcheck="false"></textarea>
+    </div>
 
 <div id="templates" style="display: none;">
     <ul>
@@ -46,14 +41,16 @@
             <ul class="listEntries"></ul>
             </li>
         <li class="listEntry">
-            <input type="checkbox">
-            <a type="text/plain" target="_blank" href=""></a>
-            <a class="fa" style="display: none;" target="_blank">&#xf05a;</a>
-            <a href="" style="display: none;" target="_blank"></a>: <!--
+            <input type="checkbox"><!--
+         --><a class="content" type="text/plain" target="_blank" href=""></a><!--
+         --><a class="fa support" href="" target="_blank">&#xf015;</a><!--
+         --><a class="fa remove" href="">&#xf00d;</a><!--
+         --><a class="fa mustread" href="" target="_blank">&#xf05a;</a><!--
+         --><span class="fa status unsecure" title="http">&#xf13e;</span><!--
          --><span class="counts dim"></span><!--
-         --><span class="status unsecure">http</span><!--
-         --><span class="status obsolete" data-i18n="3pExternalListObsolete"></span><!--
-         --><span class="status purge" data-i18n="3pExternalListPurge"></span><!--
+         --><span class="fa status failed">&#xf06a;</span><!--
+         --><span class="fa status obsolete" title="3pExternalListObsolete">&#xf071;</span><!--
+         --><span class="fa status cache">&#xf017;</span><!--
          --><span class="fa status updating">&#xf110;</span>
             </li>
         </ul>
diff --git a/src/css/3p-filters.css b/src/css/3p-filters.css
index 8aa6760f9..b3687bae1 100644
--- a/src/css/3p-filters.css
+++ b/src/css/3p-filters.css
@@ -9,14 +9,24 @@ ul {
 #options li {
     margin-bottom: 0.5em;
     }
+#listsOfBlockedHostsPrompt {
+    cursor: pointer;
+    }
+#listsOfBlockedHostsPrompt:before {
+    color: #aaa;
+    content: '\2212  ';
+    }
+body.hideUnused #listsOfBlockedHostsPrompt:before {
+    content: '+  ';
+    }
 #lists {
     margin: 0.5em 0 0 0;
-    padding-left: 1em;
+    padding-left: 0.5em;
     padding-right: 0em;
     }
 body[dir=rtl] #lists {
     padding-left: 0em;
-    padding-right: 1em;
+    padding-right: 0.5em;
     }
 #lists > li {
     margin: 0.5em 0 0 0;
@@ -45,8 +55,9 @@ body[dir=rtl] #lists {
     display: none;
     }
 li.listEntry {
+    line-height: 150%;
     margin: 0 auto 0 auto;
-    margin-left: 3em;
+    margin-left: 2.5em;
     margin-right: 0em;
     text-indent: -2em;
     }
@@ -55,26 +66,51 @@ body[dir=rtl] li.listEntry {
     margin-right: 1em;
     }
 li.listEntry > * {
+    margin-right: 0.5em;
     text-indent: 0;
     unicode-bidi: embed;
     }
-li.listEntry > a:nth-of-type(2) {
-    font-size: 16px;
-    opacity: 0.7;
+li.listEntry.toRemove > input[type="checkbox"] {
+    visibility: hidden;
     }
-li.listEntry > a:nth-of-type(2),
-li.listEntry > a:nth-of-type(2):visited {
-    color: mediumblue;
+li.listEntry.toRemove > a.content {
+    text-decoration: line-through;
     }
-li.listEntry > a:nth-of-type(2):hover {
+li.listEntry > .fa {
+    color: inherit;
+    display: none;
+    font-size: 110%;
+    opacity: 0.5;
+    vertical-align: baseline;
+    }
+li.listEntry > a.fa:hover {
     opacity: 1;
     }
-li.listEntry > a:nth-of-type(3) {
-    font-size: smaller;
-    opacity: 0.5;
+li.listEntry.support > a.support {
+    display: inline-block;
     }
+li.listEntry > a.remove,
+li.listEntry > a.remove:visited {
+    color: darkred;
+    }
+li.listEntry.external > a.remove {
+    display: inline-block;
+    }
+li.listEntry.mustread > a.mustread {
+    display: inline-block;
+    }
+li.listEntry.mustread > a.mustread:hover {
+    color: mediumblue;
+    }
+li.listEntry > .counts {
+    display: none;
+    font-size: smaller;
+}
+li.listEntry > input[type="checkbox"]:checked ~ .counts {
+    display: inline;
+}
 .dim {
-    opacity: 0.5;
+    opacity: 0.6;
     }
 #buttonApply {
     display: initial;
@@ -89,42 +125,42 @@ body[dir=rtl] #buttonApply {
 #buttonApply.disabled {
     display: none;
     }
-span.status {
-    border: 1px solid transparent;
+li.listEntry span.status {
     color: #444;
+    cursor: default;
     display: none;
-    font-size: smaller;
-    line-height: 1;
-    margin: 0 0 0 0.5em;
-    opacity: 0.8;
-    padding: 1px 2px;
 }
-span.unsecure {
-    background-color: hsl(0, 100%, 88%);
-    border-color: hsl(0, 100%, 83%);
-    }
-li.listEntry.unsecure span.unsecure {
-    display: inline;
-    }
-span.obsolete {
-    background-color: hsl(36, 100%, 80%);
-    border-color: hsl(36, 100%, 75%);
-    }
-li.listEntry.obsolete > input[type="checkbox"]:checked ~ span.obsolete {
-    display: inline;
-    }
-span.purge {
-    border-color: #ddd;
-    background-color: #eee;
-    cursor: pointer;
-    }
-span.purge:hover {
+li.listEntry span.status:hover {
     opacity: 1;
     }
-li.listEntry.cached span.purge {
-    display: inline;
+li.listEntry span.status.fa {
+    /* font-size: 110%; */
     }
-span.updating {
+li.listEntry span.unsecure {
+    color: darkred;
+    }
+li.listEntry.unsecure > input[type="checkbox"]:checked ~ span.unsecure {
+    display: inline-block;
+    }
+li.listEntry span.failed {
+    color: darkred;
+    }
+li.listEntry.failed span.failed {
+    display: inline-block;
+    }
+li.listEntry span.cache {
+    cursor: pointer;
+    }
+li.listEntry.cached:not(.updating):not(.obsolete) > input[type="checkbox"]:checked ~ span.cache {
+    display: inline-block;
+    }
+li.listEntry span.obsolete {
+    color: hsl(36, 100%, 40%);
+    }
+li.listEntry.obsolete:not(.updating) > input[type="checkbox"]:checked ~ span.obsolete {
+    display: inline-block;
+    }
+li.listEntry span.updating {
     border: none;
     padding: 0;
     }
@@ -133,14 +169,15 @@ li.listEntry.updating span.updating {
     display: inline-block;
     }
 #externalListsDiv {
-    margin: 2em auto 0 2em;
+    margin: 1.5em auto 0 1.5em;
     }
 body[dir=rtl] #externalListsDiv {
-    margin: 2em 2em 0;
+    margin: 1.5em 1.5em 0 auto;
     }
 #externalLists {
     box-sizing: border-box;
-    height: 10em;
+    height: 8em;
+    margin-top: 0.25em;
     white-space: pre;
     width: 100%;
     word-wrap: normal;
diff --git a/src/js/3p-filters.js b/src/js/3p-filters.js
index bd035874c..1b52d5276 100644
--- a/src/js/3p-filters.js
+++ b/src/js/3p-filters.js
@@ -31,7 +31,7 @@
 
 var listDetails = {},
     filteringSettingsHash = '',
-    externalLists = '';
+    lastUpdateTemplateString = vAPI.i18n('3pLastUpdate');
 
 /******************************************************************************/
 
@@ -41,10 +41,6 @@ var onMessage = function(msg) {
         updateAssetStatus(msg);
         break;
     case 'staticFilteringDataChanged':
-        filteringSettingsHash = [
-            msg.parseCosmeticFilters,
-            msg.ignoreGenericCosmeticFilters
-        ].concat(msg.listKeys.sort()).join();
         renderFilterLists();
         break;
     default:
@@ -63,12 +59,12 @@ var renderNumber = function(value) {
 
 /******************************************************************************/
 
-var renderFilterLists = function(first) {
+var renderFilterLists = function(soft) {
     var listGroupTemplate = uDom('#templates .groupEntry'),
         listEntryTemplate = uDom('#templates .listEntry'),
         listStatsTemplate = vAPI.i18n('3pListsOfBlockedHostsPerListStats'),
         renderElapsedTimeToString = vAPI.i18n.renderElapsedTimeToString,
-        lastUpdateString = vAPI.i18n('3pLastUpdate');
+        hideUnusedLists = document.body.classList.contains('hideUnused');
 
     // Assemble a pretty list name if possible
     var listNameFromListKey = function(listKey) {
@@ -92,46 +88,55 @@ var renderFilterLists = function(first) {
             elem.setAttribute('href', 'asset-viewer.html?url=' + encodeURI(listKey));
             elem.setAttribute('type', 'text/html');
             elem.textContent = listNameFromListKey(listKey) + '\u200E';
-            elem = li.querySelector('a:nth-of-type(2)');
-            if ( entry.instructionURL ) {
-                elem.setAttribute('href', entry.instructionURL);
-                elem.style.setProperty('display', '');
-            } else {
-                elem.style.setProperty('display', 'none');
-            }
-            elem = li.querySelector('a:nth-of-type(3)');
             if ( entry.supportName ) {
+                li.classList.add('support');
+                elem = li.querySelector('a.support');
                 elem.setAttribute('href', entry.supportURL);
-                elem.textContent = '(' + entry.supportName + ')';
-                elem.style.setProperty('display', '');
+                elem.setAttribute('title', entry.supportName);
             } else {
-                elem.style.setProperty('display', 'none');
+                li.classList.remove('support');
+            }
+            if ( entry.external ) {
+                li.classList.add('external');
+            } else {
+                li.classList.remove('external');
+            }
+            if ( entry.instructionURL ) {
+                li.classList.add('mustread');
+                elem = li.querySelector('a.mustread');
+                elem.setAttribute('href', entry.instructionURL);
+            } else {
+                li.classList.remove('mustread');
             }
         }
+        // https://github.com/gorhill/uBlock/issues/1429
+        if ( !soft ) {
+            elem = li.querySelector('input[type="checkbox"]');
+            elem.checked = entry.off !== true;
+        }
+        li.style.setProperty('display', hideUnusedLists && entry.off === true ? 'none' : '');
         elem = li.querySelector('span.counts');
-        var text = listStatsTemplate
-            .replace('{{used}}', renderNumber(!entry.off && !isNaN(+entry.entryUsedCount) ? entry.entryUsedCount : 0))
-            .replace('{{total}}', !isNaN(+entry.entryCount) ? renderNumber(entry.entryCount) : '?');
+        var text = '';
+        if ( !isNaN(+entry.entryUsedCount) && !isNaN(+entry.entryCount) ) {
+            text = listStatsTemplate
+                .replace('{{used}}', renderNumber(entry.off ? 0 : entry.entryUsedCount))
+                .replace('{{total}}', renderNumber(entry.entryCount));
+        }
         elem.textContent = text;
-
         // https://github.com/chrisaljoudi/uBlock/issues/104
         var asset = listDetails.cache[listKey] || {};
-
-        // https://github.com/gorhill/uBlock/issues/78
-        // Badge for non-secure connection
         var remoteURL = asset.remoteURL;
         li.classList.toggle(
             'unsecure',
             typeof remoteURL === 'string' && remoteURL.lastIndexOf('http:', 0) === 0
         );
-        // Badge for update status
-        li.classList.toggle('obsolete', entry.off !== true && asset.obsolete === true);
-        // Badge for cache status
+        li.classList.toggle('failed', asset.error !== undefined);
+        li.classList.toggle('obsolete', asset.obsolete === true);
         li.classList.toggle('cached', asset.cached === true && asset.writeTime > 0);
         if ( asset.cached ) {
-            li.querySelector('.status.purge').setAttribute(
+            li.querySelector('.status.cache').setAttribute(
                 'title',
-                lastUpdateString.replace('{{ago}}', renderElapsedTimeToString(asset.writeTime))
+                lastUpdateTemplateString.replace('{{ago}}', renderElapsedTimeToString(asset.writeTime))
             );
         }
         li.classList.remove('updating');
@@ -237,7 +242,6 @@ var renderFilterLists = function(first) {
         }
 
         uDom('#lists .listEntries .listEntry.discard').remove();
-        uDom('#buttonUpdate').toggleClass('disabled', document.querySelector('#lists .listEntry.obsolete') === null);
         uDom('#autoUpdate').prop('checked', listDetails.autoUpdate === true);
         uDom('#listsOfBlockedHostsPrompt').text(
             vAPI.i18n('3pListsOfBlockedHostsPrompt')
@@ -247,9 +251,9 @@ var renderFilterLists = function(first) {
 
         // Compute a hash of the settings so that we can keep track of changes
         // affecting the loading of filter lists.
-        if ( first ) {
-            uDom('#parseCosmeticFilters').prop('checked', listDetails.parseCosmeticFilters === true);
-            uDom('#ignoreGenericCosmeticFilters').prop('checked', listDetails.ignoreGenericCosmeticFilters === true);
+        uDom('#parseCosmeticFilters').prop('checked', listDetails.parseCosmeticFilters === true);
+        uDom('#ignoreGenericCosmeticFilters').prop('checked', listDetails.ignoreGenericCosmeticFilters === true);
+        if ( !soft ) {
             filteringSettingsHash = hashFromCurrentFromSettings();
         }
         renderWidgets();
@@ -265,16 +269,27 @@ var renderFilterLists = function(first) {
 var renderWidgets = function() {
     uDom('#buttonApply').toggleClass('disabled', filteringSettingsHash === hashFromCurrentFromSettings());
     uDom('#buttonPurgeAll').toggleClass('disabled', document.querySelector('#lists .listEntry.cached') === null);
-    uDom('#buttonUpdate').toggleClass('disabled', document.querySelector('#lists .listEntry.obsolete > input[type="checkbox"]:checked') === null);
+    uDom('#buttonUpdate').toggleClass('disabled', document.querySelector('#lists .listEntry.obsolete:not(.updating) > input[type="checkbox"]:checked') === null);
 };
 
 /******************************************************************************/
 
 var updateAssetStatus = function(details) {
-    var li = uDom('#lists .listEntry[data-listkey="' + details.key + '"]');
-    li.toggleClass('obsolete', !details.cached);
-    li.toggleClass('cached', details.cached);
-    li.removeClass('updating');
+    var li = document.querySelector('#lists .listEntry[data-listkey="' + details.key + '"]');
+    if ( li === null ) { return; }
+    li.classList.toggle('failed', !!details.failed);
+    li.classList.toggle('obsolete', !details.cached);
+    li.classList.toggle('cached', !!details.cached);
+    li.classList.remove('updating');
+    if ( details.cached ) {
+        li.querySelector('.status.cache').setAttribute(
+            'title',
+            lastUpdateTemplateString.replace(
+                '{{ago}}',
+                vAPI.i18n.renderElapsedTimeToString(Date.now())
+            )
+        );
+    }
     renderWidgets();
 };
 
@@ -291,7 +306,7 @@ var hashFromCurrentFromSettings = function() {
         document.getElementById('ignoreGenericCosmeticFilters').checked
     ];
     var listHash = [],
-        listEntries = document.querySelectorAll('#lists .listEntry[data-listkey]'),
+        listEntries = document.querySelectorAll('#lists .listEntry[data-listkey]:not(.toRemove)'),
         liEntry,
         i = listEntries.length;
     while ( i-- ) {
@@ -300,7 +315,9 @@ var hashFromCurrentFromSettings = function() {
             listHash.push(liEntry.getAttribute('data-listkey'));
         }
     }
-    return hash.concat(listHash.sort()).join();
+    hash.push(listHash.sort().join());
+    hash.push(document.getElementById('externalLists').value.trim());
+    return hash.join();
 };
 
 /******************************************************************************/
@@ -311,6 +328,18 @@ var onFilteringSettingsChanged = function() {
 
 /******************************************************************************/
 
+var onRemoveExternalList = function(ev) {
+    var liEntry = uDom(this).ancestors('[data-listkey]'),
+        listKey = liEntry.attr('data-listkey');
+    if ( listKey ) {
+        liEntry.toggleClass('toRemove');
+        renderWidgets();
+    }
+    ev.preventDefault();
+};
+
+/******************************************************************************/
+
 var onPurgeClicked = function() {
     var button = uDom(this),
         liEntry = button.ancestors('[data-listkey]'),
@@ -322,13 +351,9 @@ var onPurgeClicked = function() {
     // If the cached version is purged, the installed version must be assumed
     // to be obsolete.
     // https://github.com/gorhill/uBlock/issues/1733
-    // An external filter list must not be marked as obsolete, they will always
-    // be fetched anyways if there is no cached copy.
-    var entry = listDetails.current && listDetails.current[listKey];
-    if ( entry && entry.off !== true ) {
-        liEntry.addClass('obsolete');
-        uDom('#buttonUpdate').removeClass('disabled');
-    }
+    //   An external filter list must not be marked as obsolete, they will
+    //   always be fetched anyways if there is no cached copy.
+    liEntry.addClass('obsolete');
     liEntry.removeClass('cached');
 
     if ( liEntry.descendants('input').first().prop('checked') ) {
@@ -351,24 +376,41 @@ var selectFilterLists = function(callback) {
         value: document.getElementById('ignoreGenericCosmeticFilters').checked
     });
 
-    // Filter lists
-    var listKeys = [],
-        liEntries = document.querySelectorAll('#lists .listEntry[data-listkey]'),
+    // Filter lists to select
+    var toSelect = [],
+        liEntries = document.querySelectorAll('#lists .listEntry[data-listkey]:not(.toRemove)'),
         i = liEntries.length,
         liEntry;
     while ( i-- ) {
         liEntry = liEntries[i];
         if ( liEntry.querySelector('input[type="checkbox"]:checked') !== null ) {
-            listKeys.push(liEntry.getAttribute('data-listkey'));
+            toSelect.push(liEntry.getAttribute('data-listkey'));
         }
     }
 
+    // External filter lists to remove
+    var toRemove = [];
+    liEntries = document.querySelectorAll('#lists .listEntry.toRemove[data-listkey]');
+    i = liEntries.length;
+    while ( i-- ) {
+        toRemove.push(liEntries[i].getAttribute('data-listkey'));
+    }
+
+    // External filter lists to import
+    var externalListsElem = document.getElementById('externalLists'),
+        toImport = externalListsElem.value.trim();
+    externalListsElem.value = '';
+
     messaging.send(
         'dashboard',
-        { what: 'selectFilterLists', keys: listKeys },
+        {
+            what: 'applyFilterListSelection',
+            toSelect: toSelect,
+            toImport: toImport,
+            toRemove: toRemove
+        },
         callback
     );
-
     filteringSettingsHash = hashFromCurrentFromSettings();
 };
 
@@ -387,8 +429,11 @@ var buttonApplyHandler = function() {
 
 var buttonUpdateHandler = function() {
     var onSelectionDone = function() {
-        uDom('#lists .listEntry.obsolete').addClass('updating');
+        uDom('#lists .listEntry.obsolete > input[type="checkbox"]:checked')
+            .ancestors('.listEntry[data-listkey]')
+            .addClass('updating');
         messaging.send('dashboard', { what: 'forceUpdateAssets' });
+        renderWidgets();
     };
     selectFilterLists(onSelectionDone);
     renderWidgets();
@@ -404,7 +449,7 @@ var buttonPurgeAllHandler = function(ev) {
             what: 'purgeAllCaches',
             hard: ev.ctrlKey && ev.shiftKey
         },
-        renderFilterLists   
+        function() { renderFilterLists(true); }
     );
 };
 
@@ -423,39 +468,13 @@ var autoUpdateCheckboxChanged = function() {
 
 /******************************************************************************/
 
-var renderExternalLists = function() {
-    var onReceived = function(details) {
-        uDom('#externalLists').val(details);
-        externalLists = details;
-    };
-    messaging.send(
-        'dashboard',
-        { what: 'userSettings', name: 'externalLists' },
-        onReceived
-    );
-};
-
-/******************************************************************************/
-
-var externalListsChangeHandler = function() {
-    uDom.nodeFromId('externalListsApply').disabled =
-        uDom.nodeFromId('externalLists').value.trim() === externalLists.trim();
-};
-
-/******************************************************************************/
-
-var externalListsApplyHandler = function() {
-    externalLists = uDom.nodeFromId('externalLists').value;
-    messaging.send(
-        'dashboard',
-        {
-            what: 'userSettings',
-            name: 'externalLists',
-            value: externalLists
-        }
-    );
-    renderFilterLists();
-    uDom('#externalListsApply').prop('disabled', true);
+var toggleUnusedLists = function() {
+    document.body.classList.toggle('hideUnused');
+    var hide = document.body.classList.contains('hideUnused');
+    uDom('#lists li.listEntry > input[type="checkbox"]:not(:checked)')
+        .ancestors('li.listEntry[data-listkey]')
+        .css('display', hide ? 'none' : '');
+    vAPI.localStorage.setItem('hideUnusedFilterLists', hide ? '1' : '0');
 };
 
 /******************************************************************************/
@@ -478,7 +497,7 @@ var toCloudData = function() {
         parseCosmeticFilters: uDom.nodeFromId('parseCosmeticFilters').checked,
         ignoreGenericCosmeticFilters: uDom.nodeFromId('ignoreGenericCosmeticFilters').checked,
         selectedLists: [],
-        externalLists: externalLists
+        externalLists: listDetails.externalLists
     };
 
     var liEntries = uDom('#lists .listEntry'), liEntry;
@@ -529,7 +548,6 @@ var fromCloudData = function(data, append) {
     elem.value += data.externalLists || '';
 
     renderWidgets();
-    externalListsChangeHandler();
 };
 
 self.cloud.onPush = toCloudData;
@@ -537,20 +555,25 @@ self.cloud.onPull = fromCloudData;
 
 /******************************************************************************/
 
+document.body.classList.toggle(
+    'hideUnused',
+    vAPI.localStorage.getItem('hideUnusedFilterLists') === '1'
+);
+
 uDom('#autoUpdate').on('change', autoUpdateCheckboxChanged);
 uDom('#parseCosmeticFilters').on('change', onFilteringSettingsChanged);
 uDom('#ignoreGenericCosmeticFilters').on('change', onFilteringSettingsChanged);
 uDom('#buttonApply').on('click', buttonApplyHandler);
 uDom('#buttonUpdate').on('click', buttonUpdateHandler);
 uDom('#buttonPurgeAll').on('click', buttonPurgeAllHandler);
-uDom('#lists').on('change', '.listEntry > input', onFilteringSettingsChanged);
-uDom('#lists').on('click', 'span.purge', onPurgeClicked);
-uDom('#externalLists').on('input', externalListsChangeHandler);
-uDom('#externalListsApply').on('click', externalListsApplyHandler);
+uDom('#listsOfBlockedHostsPrompt').on('click', toggleUnusedLists);
 uDom('#lists').on('click', '.groupEntry > span', groupEntryClickHandler);
+uDom('#lists').on('change', '.listEntry > input', onFilteringSettingsChanged);
+uDom('#lists').on('click', '.listEntry > a.remove', onRemoveExternalList);
+uDom('#lists').on('click', 'span.cache', onPurgeClicked);
+uDom('#externalLists').on('input', onFilteringSettingsChanged);
 
-renderFilterLists(true);
-renderExternalLists();
+renderFilterLists();
 
 /******************************************************************************/
 
diff --git a/src/js/assets.js b/src/js/assets.js
index 20f38aded..9a29812d7 100644
--- a/src/js/assets.js
+++ b/src/js/assets.js
@@ -96,7 +96,7 @@ var getTextFileFromURL = function(url, onLoad, onError) {
 
     var onErrorReceived = function() {
         this.onload = this.onerror = this.ontimeout = null;
-        µBlock.logger.writeOne('', 'error', errorCantConnectTo.replace('{{msg}}', ''));
+        µBlock.logger.writeOne('', 'error', errorCantConnectTo.replace('{{msg}}', url));
         onError.call(this);
     };
 
@@ -805,7 +805,11 @@ var getRemote = function(assetKey, callback) {
     };
 
     var onRemoteContentError = function() {
-        registerAssetSource(assetKey, { error: { time: Date.now(), error: this.statusText } });
+        var text = this.statusText;
+        if ( this.status === 0 ) {
+            text = 'network error';
+        }
+        registerAssetSource(assetKey, { error: { time: Date.now(), error: text } });
         tryLoading();
     };
 
@@ -948,6 +952,8 @@ var updateNext = function() {
             if ( details.assetKey === 'assets.json' ) {
                 updateAssetSourceRegistry(details.content);
             }
+        } else {
+            fireNotification('asset-update-failed', { assetKey: details.assetKey });
         }
         if ( findOne() !== undefined ) {
             vAPI.setTimeout(updateNext, updaterAssetDelay);
diff --git a/src/js/background.js b/src/js/background.js
index 08c56ba50..5cc6d8915 100644
--- a/src/js/background.js
+++ b/src/js/background.js
@@ -127,6 +127,7 @@ return {
     userFiltersPath: 'user-filters',
     pslAssetKey: 'public_suffix_list.dat',
 
+    selectedFilterLists: [],
     availableFilterLists: {},
 
     selfieAfter: 23 * oneMinute,
diff --git a/src/js/messaging.js b/src/js/messaging.js
index 4cc466f7c..d5c780b69 100644
--- a/src/js/messaging.js
+++ b/src/js/messaging.js
@@ -94,10 +94,8 @@ var onMessage = function(request, sender, callback) {
     var response;
 
     switch ( request.what ) {
-    case 'mouseClick':
-        µb.mouseX = request.x;
-        µb.mouseY = request.y;
-        µb.mouseURL = request.url;
+    case 'applyFilterListSelection':
+        response = µb.applyFilterListSelection(request);
         break;
 
     case 'compileCosmeticFilterSelector':
@@ -147,6 +145,12 @@ var onMessage = function(request, sender, callback) {
         µb.openNewTab(request.details);
         break;
 
+    case 'mouseClick':
+        µb.mouseX = request.x;
+        µb.mouseY = request.y;
+        µb.mouseURL = request.url;
+        break;
+
     case 'reloadTab':
         if ( vAPI.isBehindTheSceneTabId(request.tabId) === false ) {
             vAPI.tabs.reload(request.tabId);
@@ -160,10 +164,6 @@ var onMessage = function(request, sender, callback) {
         µb.scriptlets.report(tabId, request.scriptlet, request.response);
         break;
 
-    case 'selectFilterLists':
-        µb.saveSelectedFilterLists(request.keys, request.append);
-        break;
-
     case 'setWhitelist':
         µb.netWhitelist = µb.whitelistFromString(request.whitelist);
         µb.saveWhitelist();
@@ -873,11 +873,12 @@ var getLists = function(callback) {
         autoUpdate: µb.userSettings.autoUpdate,
         available: null,
         cache: null,
-        parseCosmeticFilters: µb.userSettings.parseAllABPHideFilters,
         cosmeticFilterCount: µb.cosmeticFilteringEngine.getFilterCount(),
         current: µb.availableFilterLists,
+        externalLists: µb.userSettings.externalLists,
         ignoreGenericCosmeticFilters: µb.userSettings.ignoreGenericCosmeticFilters,
         netFilterCount: µb.staticNetFilteringEngine.getFilterCount(),
+        parseCosmeticFilters: µb.userSettings.parseAllABPHideFilters,
         userFiltersPath: µb.userFiltersPath,
         aliases: µb.assets.listKeyAliases
     };
@@ -1287,8 +1288,7 @@ var onMessage = function(request, sender, callback) {
 
     case 'subscriberData':
         response = {
-            confirmStr: vAPI.i18n('subscriberConfirm'),
-            externalLists: µBlock.userSettings.externalLists
+            confirmStr: vAPI.i18n('subscriberConfirm')
         };
         break;
 
diff --git a/src/js/scriptlets/subscriber.js b/src/js/scriptlets/subscriber.js
index 887e95db8..4250c5ff1 100644
--- a/src/js/scriptlets/subscriber.js
+++ b/src/js/scriptlets/subscriber.js
@@ -19,7 +19,7 @@
     Home: https://github.com/gorhill/uBlock
 */
 
-/* global vAPI, HTMLDocument */
+/* global HTMLDocument */
 
 'use strict';
 
@@ -79,9 +79,7 @@ var onAbpLinkClicked = function(ev) {
     var matches = /^abp:\/*subscribe\/*\?location=([^&]+).*title=([^&]+)/.exec(href);
     if ( matches === null ) {
         matches = /^https?:\/\/.*?[&?]location=([^&]+).*?&title=([^&]+)/.exec(href);
-        if ( matches === null ) {
-            return;
-        }
+        if ( matches === null ) { return; }
     }
 
     var location = decodeURIComponent(matches[1]);
@@ -95,44 +93,18 @@ var onAbpLinkClicked = function(ev) {
         messaging.send('scriptlets', { what: 'reloadAllFilters' });
     };
 
-    var onExternalListsSaved = function() {
-        messaging.send(
-            'scriptlets',
-            {
-                what: 'selectFilterLists',
-                keys: [ location ],
-                append: true
-            },
-            onListsSelectionDone
-        );
-    };
-
     var onSubscriberDataReady = function(details) {
         var confirmStr = details.confirmStr
                             .replace('{{url}}', location)
                             .replace('{{title}}', title);
-        if ( !window.confirm(confirmStr) ) {
-            return;
-        }
-
-        // List already subscribed to?
-        // https://github.com/chrisaljoudi/uBlock/issues/1033
-        // Split on line separators, not whitespaces.
-        var text = details.externalLists.trim();
-        var lines = text !== '' ? text.split(/\s*[\n\r]+\s*/) : [];
-        if ( lines.indexOf(location) !== -1 ) {
-            return;
-        }
-        lines.push(location, '');
-
+        if ( !window.confirm(confirmStr) ) { return; }
         messaging.send(
             'scriptlets',
             {
-                what: 'userSettings',
-                name: 'externalLists',
-                value: lines.join('\n')
+                what: 'applyFilterListSelection',
+                toImport: location
             },
-            onExternalListsSaved
+            onListsSelectionDone
         );
     };
 
diff --git a/src/js/storage.js b/src/js/storage.js
index 6b0711853..782d2da24 100644
--- a/src/js/storage.js
+++ b/src/js/storage.js
@@ -186,28 +186,33 @@
             // Uncomment when all have moved to v1.11 and beyond.
             //vAPI.storage.remove('remoteBlacklists');
         }
+        µb.selectedFilterLists = listKeys.slice();
         callback(listKeys);
     });
 };
 
-µBlock.saveSelectedFilterLists = function(listKeys, append) {
+µBlock.saveSelectedFilterLists = function(newKeys, append) {
     var µb = this;
-    var save = function(keys) {
-        var uniqueKeys = µb.setToArray(new Set(keys));
+    this.loadSelectedFilterLists(function(oldKeys) {
+        oldKeys = oldKeys || [];
+        if ( append ) {
+            newKeys = newKeys.concat(oldKeys);
+        }
+        var newSet = new Set(newKeys);
+        // Purge unused filter lists from cache.
+        for ( var i = 0, n = oldKeys.length; i < n; i++ ) {
+            if ( newSet.has(oldKeys[i]) === false ) {
+                µb.removeFilterList(oldKeys[i]);
+            }
+        }
+        newKeys = µb.setToArray(newSet);
         var bin = {
-            selectedFilterLists: uniqueKeys,
-            remoteBlacklists: µb.oldDataFromNewListKeys(uniqueKeys)
+            selectedFilterLists: newKeys,
+            remoteBlacklists: µb.oldDataFromNewListKeys(newKeys)
         };
+        µb.selectedFilterLists = newKeys;
         vAPI.storage.set(bin);
-    };
-    if ( append ) {
-        this.loadSelectedFilterLists(function(keys) {
-            listKeys = listKeys.concat(keys || []);
-            save(listKeys);
-        });
-    } else {
-        save(listKeys);
-    }
+    });
 };
 
 // TODO(seamless migration):
@@ -262,6 +267,113 @@
 
 /******************************************************************************/
 
+µBlock.applyFilterListSelection = function(details, callback) {
+    var µb = this,
+        selectedListKeySet = new Set(this.selectedFilterLists),
+        externalLists = this.userSettings.externalLists,
+        i, n, assetKey;
+
+    // Filter lists to select
+    if ( Array.isArray(details.toSelect) ) {
+        if ( details.merge ) {
+            for ( i = 0, n = details.toSelect.length; i < n; i++ ) {
+                selectedListKeySet.add(details.toSelect[i]);
+            }
+        } else {
+            selectedListKeySet = new Set(details.toSelect);
+        }
+    }
+
+    // Imported filter lists to remove
+    if ( Array.isArray(details.toRemove) ) {
+        var removeURLFromHaystack = function(haystack, needle) {
+            return haystack.replace(
+                new RegExp(
+                    '(^|\\n)' +
+                    needle.replace(/[.*+?^${}()|[\]\\]/g, '\\$&') +
+                    '(\\n|$)', 'g'),
+                '\n'
+            ).trim();
+        };
+        for ( i = 0, n = details.toRemove.length; i < n; i++ ) {
+            assetKey = details.toRemove[i];
+            selectedListKeySet.delete(assetKey);
+            externalLists = removeURLFromHaystack(externalLists, assetKey);
+            this.removeFilterList(assetKey);
+        }
+    }
+
+    // Filter lists to import
+    if ( typeof details.toImport === 'string' ) {
+        // https://github.com/gorhill/uBlock/issues/1181
+        //   Try mapping the URL of an imported filter list to the assetKey of an
+        //   existing stock list.
+        var assetKeyFromURL = function(url) {
+            var needle = url.replace(/^https?:/, '');
+            var assets = µb.availableFilterLists, asset;
+            for ( var assetKey in assets ) {
+                asset = assets[assetKey];
+                if ( asset.content !== 'filters' ) { continue; }
+                if ( typeof asset.contentURL === 'string' ) {
+                    if ( asset.contentURL.endsWith(needle) ) { return assetKey; }
+                    continue;
+                }
+                if ( Array.isArray(asset.contentURL) === false ) { continue; }
+                for ( i = 0, n = asset.contentURL.length; i < n; i++ ) {
+                    if ( asset.contentURL[i].endsWith(needle) ) {
+                        return assetKey;
+                    }
+                }
+            }
+            return url;
+        };
+        var importedSet = new Set(this.listKeysFromCustomFilterLists(externalLists)),
+            toImportSet = new Set(this.listKeysFromCustomFilterLists(details.toImport)),
+            iter = toImportSet.values();
+        for (;;) {
+            var entry = iter.next();
+            if ( entry.done ) { break; }
+            if ( importedSet.has(entry.value) ) { continue; }
+            assetKey = assetKeyFromURL(entry.value);
+            if ( assetKey === entry.value ) {
+                importedSet.add(entry.value);
+            }
+            selectedListKeySet.add(assetKey);
+        }
+        externalLists = this.setToArray(importedSet).sort().join('\n');
+    }
+
+    var result = this.setToArray(selectedListKeySet);
+    if ( externalLists !== this.userSettings.externalLists ) {
+        this.userSettings.externalLists = externalLists;
+        vAPI.storage.set({ externalLists: externalLists });
+    }
+    this.saveSelectedFilterLists(result);
+    if ( typeof callback === 'function' ) {
+        callback(result);
+    }
+};
+
+/******************************************************************************/
+
+µBlock.listKeysFromCustomFilterLists = function(raw) {
+    var out = new Set(),
+        reIgnore = /^[!#]/,
+        reValid = /^[a-z-]+:\/\/\S+/,
+        lineIter = new this.LineIterator(raw),
+        location;
+    while ( lineIter.eot() === false ) {
+        location = lineIter.next().trim();
+        if ( reIgnore.test(location) || !reValid.test(location) ) {
+            continue;
+        }
+        out.add(location);
+    }
+    return this.setToArray(out);
+};
+
+/******************************************************************************/
+
 µBlock.saveUserFilters = function(content, callback) {
     // https://github.com/gorhill/uBlock/issues/1022
     // Be sure to end with an empty line.
@@ -315,21 +427,6 @@
 
 /******************************************************************************/
 
-µBlock.listKeysFromCustomFilterLists = function(raw) {
-    var out = {};
-    var reIgnore = /^[!#]|[^0-9A-Za-z!*'();:@&=+$,\/?%#\[\]_.~-]/,
-        lineIter = new this.LineIterator(raw),
-        location;
-    while ( lineIter.eot() === false ) {
-        location = lineIter.next().trim();
-        if ( location === '' || reIgnore.test(location) ) { continue; }
-        out[location] = true;
-    }
-    return Object.keys(out);
-};
-
-/******************************************************************************/
-
 µBlock.autoSelectRegionalFilterLists = function(lists) {
     var lang = self.navigator.language.slice(0, 2),
         selectedListKeys = [],
@@ -351,41 +448,6 @@
 
 /******************************************************************************/
 
-µBlock.changeExternalFilterLists = function(before, after) {
-    var µb = µBlock;
-    var onLoaded = function(keys) {
-        var fullDict = new Set(keys || []),
-            mustSave = false,
-            oldKeys = µb.listKeysFromCustomFilterLists(before),
-            oldDict = new Set(oldKeys),
-            newKeys = µb.listKeysFromCustomFilterLists(after),
-            newDict = new Set(newKeys),
-            i, key;
-        i = oldKeys.length;
-        while ( i-- ) {
-            key = oldKeys[i];
-            if ( fullDict.has(key) && !newDict.has(key) ) {
-                fullDict.delete(key);
-                mustSave = true;
-            }
-        }
-        i = newKeys.length;
-        while ( i-- ) {
-            key = newKeys[i];
-            if ( !fullDict.has(key) && !oldDict.has(key) ) {
-                fullDict.add(key);
-                mustSave = true;
-            }
-        }
-        if ( mustSave ) {
-            µb.saveSelectedFilterLists(µb.setToArray(fullDict));
-        }
-    };
-    this.loadSelectedFilterLists(onLoaded);
-};
-
-/******************************************************************************/
-
 µBlock.getAvailableLists = function(callback) {
     var µb = this,
         oldAvailableLists = {},
@@ -1006,7 +1068,7 @@
     if ( topic === 'before-asset-updated' ) {
         if (
             this.availableFilterLists.hasOwnProperty(details.assetKey) &&
-            this.availableFilterLists[details.assetKey].off === true
+            this.selectedFilterLists.indexOf(details.assetKey) === -1
         ) {
             return false;
         }
@@ -1018,7 +1080,7 @@
         var cached = typeof details.content === 'string' && details.content !== '';
         if ( this.availableFilterLists.hasOwnProperty(details.assetKey) ) {
             if ( cached ) {
-                if ( this.availableFilterLists[details.assetKey].off !== true ) {
+                if ( this.selectedFilterLists.indexOf(details.assetKey) !== -1 ) {
                     this.extractFilterListMetadata(
                         details.assetKey,
                         details.content
@@ -1049,6 +1111,16 @@
         return;
     }
 
+    // Update failed.
+    if ( topic === 'asset-update-failed' ) {
+        vAPI.messaging.broadcast({
+            what: 'assetUpdated',
+            key: details.assetKey,
+            failed: true
+        });
+        return;
+    }
+
     // Reload all filter lists if needed.
     if ( topic === 'after-assets-updated' ) {
         if ( details.assetKeys.length !== 0 ) {
diff --git a/src/js/ublock.js b/src/js/ublock.js
index f765fbd74..18c61e5cd 100644
--- a/src/js/ublock.js
+++ b/src/js/ublock.js
@@ -317,9 +317,6 @@ var reInvalidHostname = /[^a-z0-9.\-\[\]:]/,
 
     // Pre-change
     switch ( name ) {
-    case 'externalLists':
-        this.changeExternalFilterLists(us.externalLists, value);
-        break;
     case 'largeMediaSize':
         if ( typeof value !== 'number' ) {
             value = parseInt(value, 10) || 0;