diff --git a/src/js/1p-filters.js b/src/js/1p-filters.js
index c4f7590df..7e20a30c2 100644
--- a/src/js/1p-filters.js
+++ b/src/js/1p-filters.js
@@ -111,12 +111,12 @@ function currentStateChanged() {
 }
 
 function getEditorText() {
-    const text = cmEditor.getValue().replace(/\s+$/, '');
+    const text = cmEditor.getValue().trimEnd();
     return text === '' ? text : `${text}\n`;
 }
 
 function setEditorText(text) {
-    cmEditor.setValue(text.replace(/\s+$/, '') + '\n\n');
+    cmEditor.setValue(`${text.trimEnd()}\n\n`);
 }
 
 /******************************************************************************/
diff --git a/src/js/arglist-parser.js b/src/js/arglist-parser.js
index d8200df58..708029e2d 100644
--- a/src/js/arglist-parser.js
+++ b/src/js/arglist-parser.js
@@ -32,7 +32,7 @@ export class ArglistParser {
         this.transform = false;
         this.failed = false;
         this.reWhitespaceStart = /^\s+/;
-        this.reWhitespaceEnd = /\s+$/;
+        this.reWhitespaceEnd = /(?:^|\S)(\s+)$/;
         this.reOddTrailingEscape = /(?:^|[^\\])(?:\\\\)*\\$/;
         this.reTrailingEscapeChars = /\\+$/;
     }
@@ -90,7 +90,7 @@ export class ArglistParser {
     }
     rightWhitespaceCount(s) {
         const match = this.reWhitespaceEnd.exec(s);
-        return match === null ? 0 : match[0].length;
+        return match === null ? 0 : match[1].length;
     }
     indexOfNextArgSeparator(pattern, separatorCode) {
         this.argBeg = this.argEnd = separatorCode !== this.separatorCode
diff --git a/src/js/static-filtering-parser.js b/src/js/static-filtering-parser.js
index 66d2853ae..a3f6e1cc5 100644
--- a/src/js/static-filtering-parser.js
+++ b/src/js/static-filtering-parser.js
@@ -785,7 +785,7 @@ export class AstFilterParser {
         this.selectorCompiler = new ExtSelectorCompiler(options);
         // Regexes
         this.reWhitespaceStart = /^\s+/;
-        this.reWhitespaceEnd = /\s+$/;
+        this.reWhitespaceEnd = /(?:^|\S)(\s+)$/;
         this.reCommentLine = /^(?:!|#\s|####|\[adblock)/i;
         this.reExtAnchor = /(#@?(?:\$\?|\$|%|\?)?#).{1,2}/;
         this.reInlineComment = /(?:\s+#).*?$/;
@@ -2786,7 +2786,7 @@ export class AstFilterParser {
 
     rightWhitespaceCount(s) {
         const match = this.reWhitespaceEnd.exec(s);
-        return match === null ? 0 : match[0].length;
+        return match === null ? 0 : match[1].length;
     }
 
     nextCommaInCommaSeparatedListString(s, start) {
diff --git a/src/js/whitelist.js b/src/js/whitelist.js
index 6d9e951c1..371d25f99 100644
--- a/src/js/whitelist.js
+++ b/src/js/whitelist.js
@@ -99,12 +99,12 @@ uBlockDashboard.patchCodeMirrorEditor(cmEditor);
 /******************************************************************************/
 
 function getEditorText() {
-    let text = cmEditor.getValue().replace(/\s+$/, '');
-    return text === '' ? text : text + '\n';
+    const text = cmEditor.getValue().trimEnd();
+    return text === '' ? text : `${text}\n`;
 }
 
 function setEditorText(text) {
-    cmEditor.setValue(text.replace(/\s+$/, '') + '\n');
+    cmEditor.setValue(`${text.trimEnd()}\n`);
 }
 
 /******************************************************************************/