diff --git a/js/contentscript-end.js b/js/contentscript-end.js
index fb6d0be8c..ef2f2b81d 100644
--- a/js/contentscript-end.js
+++ b/js/contentscript-end.js
@@ -153,6 +153,9 @@ var uBlockMessaging = (function(name){
             while ( i-- ) {
                 injectedSelectors[selectors[i]] = true;
             }
+            // https://github.com/gorhill/uBlock/issues/158
+            // Ensure injected styles are enforced
+            hideElements(selectors.join(','));
         }
         idsFromNodeList(document.querySelectorAll('[id]'));
         classesFromNodeList(document.querySelectorAll('[class]'));
@@ -239,7 +242,7 @@ var uBlockMessaging = (function(name){
             }
         }
         if ( hideSelectors.length ) {
-            applyCSS(hideSelectors, 'display', 'none');
+            hideElements(hideSelectors);
             var style = document.createElement('style');
             style.setAttribute('class', 'ublock-postload-1ae7a5f130fc79b4fdb8a4272d9426b5');
             // The linefeed before the style block is very important: do no remove!
@@ -259,14 +262,16 @@ var uBlockMessaging = (function(name){
         contextNodes.length = 0;
     };
 
-    var applyCSS = function(selectors, prop, value) {
+    var hideElements = function(selectors) {
         if ( document.body === null ) {
             return;
         }
+        // https://github.com/gorhill/uBlock/issues/158
+        // Using CSSStyleDeclaration.setProperty is more reliable
         var elems = document.querySelectorAll(selectors);
         var i = elems.length;
         while ( i-- ) {
-            elems[i].style[prop] = value;
+            elems[i].style.setProperty('display', 'none', 'important');
         }
     };
 
diff --git a/js/contentscript-start.js b/js/contentscript-start.js
index 0c2bcb4ee..2554bd19f 100644
--- a/js/contentscript-start.js
+++ b/js/contentscript-start.js
@@ -161,7 +161,7 @@ var cosmeticFilters = function(details) {
     }
     if ( hide.length !== 0 ) {
         var text = hide.join(',\n');
-        applyCSS(text, 'display', 'none');
+        hideElements(text);
         // The linefeed before the style block is very important: do no remove!
         style.appendChild(document.createTextNode(text + '\n{display:none !important;}'));
         //console.debug('µBlock> "%s" cosmetic filters: injecting %d CSS rules:', details.domain, details.hide.length, hideStyleText);
@@ -185,6 +185,7 @@ var netFilters = function(details) {
         '\n{visibility:hidden !important;}';
     style.appendChild(document.createTextNode(text + css));
     parent.appendChild(style);
+    //console.debug('document.querySelectorAll("%s") = %o', text, document.querySelectorAll(text));
 };
 
 var filteringHandler = function(details) {
@@ -199,14 +200,16 @@ var filteringHandler = function(details) {
     }
 };
 
-var applyCSS = function(selectors, prop, value) {
+var hideElements = function(selectors) {
     if ( document.body === null ) {
         return;
     }
+    // https://github.com/gorhill/uBlock/issues/158
+    // Using CSSStyleDeclaration.setProperty is more reliable
     var elems = document.querySelectorAll(selectors);
     var i = elems.length;
     while ( i-- ) {
-        elems[i].style[prop] = value;
+        elems[i].style.setProperty('display', 'none', 'important');
     }
 };