diff --git a/src/css/codemirror.css b/src/css/codemirror.css
index f784f6069..7e95eb5ce 100644
--- a/src/css/codemirror.css
+++ b/src/css/codemirror.css
@@ -24,7 +24,7 @@
 
 /* CodeMirror theme overrides */
 .cm-s-default .cm-value { color: #930; }
-.cm-s-default .cm-comment { color: #777; }
+.cm-s-default .cm-comment { color: var(--sf-comment-ink); }
 .cm-s-default .cm-keyword { color: #90b; }
 .cm-s-default .cm-regex {
     text-underline-position: under;
@@ -41,6 +41,16 @@
     text-decoration: underline red;
     text-underline-position: under;
     }
+.cm-s-default .cm-warning {
+    text-decoration: underline var(--sf-warning-ink);
+    text-underline-position: under;
+    }
+.cm-s-default .cm-link {
+    text-decoration: none;
+    }
+.cm-s-default .cm-link:hover {
+    color: var(--link-ink);
+    }
 
 .cm-directive { color: #333; font-weight: bold; }
 .cm-staticext { color: #008; }
diff --git a/src/css/themes/default.css b/src/css/themes/default.css
index de3f8f644..9f271e076 100644
--- a/src/css/themes/default.css
+++ b/src/css/themes/default.css
@@ -159,6 +159,10 @@
     --bg-popup-cell-block-own: hsla(0, 100%, 40%, 1);
     --bg-popup-cell-label-mixed: hsla(45, 100%, 38%, 1);
     --popup-icon-x-ink: var(--red-60);
+
+    /* syntax highlight: static filtering */
+    --sf-comment-ink: var(--light-gray-90);
+    --sf-warning-ink: var(--yellow-50);
 }
 
 /**
diff --git a/src/js/codemirror/ubo-static-filtering.js b/src/js/codemirror/ubo-static-filtering.js
index 24d257d60..7f6299dfe 100644
--- a/src/js/codemirror/ubo-static-filtering.js
+++ b/src/js/codemirror/ubo-static-filtering.js
@@ -44,22 +44,33 @@ CodeMirror.defineMode('ubo-static-filtering', function() {
     if ( StaticFilteringParser instanceof Object === false ) { return; }
     const parser = new StaticFilteringParser({ interactive: true });
 
+    const reURL = /\bhttps?:\/\/\S+/;
     const rePreparseDirectives = /^!#(?:if|endif|include )\b/;
     const rePreparseIfDirective = /^(!#if ?)(.*)$/;
     let parserSlot = 0;
     let netOptionValueMode = false;
 
     const colorCommentSpan = function(stream) {
-        if ( rePreparseDirectives.test(stream.string) === false ) {
+        const { string, pos } = stream;
+        if ( rePreparseDirectives.test(string) === false ) {
+            const match = reURL.exec(string.slice(pos));
+            if ( match !== null ) {
+                if ( match.index === 0 ) {
+                    stream.pos += match[0].length;
+                    return 'comment link';
+                }
+                stream.pos += match.index;
+                return 'comment';
+            }
             stream.skipToEnd();
             return 'comment';
         }
-        const match = rePreparseIfDirective.exec(stream.string);
+        const match = rePreparseIfDirective.exec(string);
         if ( match === null ) {
             stream.skipToEnd();
             return 'variable strong';
         }
-        if ( stream.pos < match[1].length ) {
+        if ( pos < match[1].length ) {
             stream.pos += match[1].length;
             return 'variable strong';
         }
@@ -95,19 +106,29 @@ CodeMirror.defineMode('ubo-static-filtering', function() {
     };
 
     const colorExtScriptletPatternSpan = function(stream) {
+        const { pos, string } = stream;
         const { i, len } = parser.patternSpan;
-        if ( stream.pos === parser.slices[i+1] ) {
-            stream.pos += 4;
+        const patternBeg = parser.slices[i+1];
+        if ( pos === patternBeg ) {
+            stream.pos = pos + 4;
             return 'def';
         }
         if ( len > 3 ) {
+            if ( pos === patternBeg + 4 ) {
+                const match = /^[^,)]+/.exec(string.slice(pos));
+                const token = match && match[0].trim();
+                if ( token && scriptletNames.has(token) === false ) {
+                    stream.pos = pos + match[0].length;
+                    return 'warning';
+                }
+            }
             const r = parser.slices[i+len+1] - 1;
-            if ( stream.pos < r ) {
+            if ( pos < r ) {
                 stream.pos = r;
                 return 'variable';
             }
-            if ( stream.pos === r ) {
-                stream.pos += 1;
+            if ( pos === r ) {
+                stream.pos = pos + 1;
                 return 'def';
             }
         }
@@ -483,7 +504,6 @@ const initHints = function() {
 /******************************************************************************/
 
 CodeMirror.registerHelper('fold', 'ubo-static-filtering', (( ) => {
-
     const foldIfEndif = function(startLineNo, startLine, cm) {
         const lastLineNo = cm.lastLine();
         let endLineNo = startLineNo;
@@ -539,6 +559,50 @@ CodeMirror.registerHelper('fold', 'ubo-static-filtering', (( ) => {
 
 /******************************************************************************/
 
+// Enhanced word selection
+
+{
+    const Pass = CodeMirror.Pass;
+
+    const selectWordAt = function(cm, pos) {
+        const { line, ch } = pos;
+
+        // Leave current selection alone
+        if ( cm.somethingSelected() ) {
+            const from = cm.getCursor('from');
+            const to = cm.getCursor('to');
+            if (
+                (line > from.line || line === from.line && ch > from.ch) &&
+                (line < to.line || line === to.line && ch < to.ch)
+            ) {
+                return Pass;
+            }
+        }
+        const s = cm.getLine(line);
+
+        // Select URL
+        let lmatch = /\bhttps?:\/\/\S+$/.exec(s.slice(0, ch));
+        let rmatch = /^\S+/.exec(s.slice(ch));
+
+        // TODO: add more convenient word-matching cases here
+        // if ( lmatch === null || rmatch === null ) { ... }
+
+        if ( lmatch === null || rmatch === null ) { return Pass; }
+        cm.setSelection(
+            { line, ch: lmatch.index },
+            { line, ch: ch + rmatch.index + rmatch[0].length }
+        );
+    };
+
+    CodeMirror.defineInitHook(cm => {
+        cm.addKeyMap({
+            'LeftDoubleClick': selectWordAt,
+        });
+    });
+}
+
+/******************************************************************************/
+
 // <<<<< end of local scope
 }