Ticket #3372: 3372.patch

_source/plugins/undo/plugin.js

@@ -82 +82 @@
                                                                 {
                                                                         // Do not capture CTRL hotkeys.
                                                                         if ( !event.data.$.ctrlKey && !event.data.$.metaKey )
-                                                                                undoManager.type();
+                                                                                undoManager.type( event );
                                                                 });
 
                                                         // Being this the first call, let's get an undo snapshot.
@@ -182 +182 @@
                 this.index = -1;
 
                 this.limit = editor.config.undoStackSize;
+
+                /**
+                 * Remember last pressed key.
+                 */
+                this.lastKeystroke = 0;
         }
 
         UndoManager.prototype =
         {
-                type : function()
+                /**
+                 *
+                 * @param {CKEDITOR.dom.event} [event]
+                 */
+                type : function( event )
                 {
-                        if ( !this.typing )
+                        var keystroke = event && event.data.getKeystroke(),
+                                /**
+                                 * Backspace not preceeded by backspace.
+                                 */
+                                safeBackspace = keystroke == 8 && !( this.lastKeystroke == 8 );
+                        
+                        if ( !this.typing || safeBackspace )
                         {
                                 var beforeTypeImage = new Image( this.editor );
 
@@ -219 +234 @@
                                                         this.onChange();
                                                 }
                                         },
-                                        0, this );
+                                        0, this
+                                );
 
-                                return;
+                                if ( !safeBackspace )
+                                        return;
                         }
 
                         this.typesCount++;
@@ -233 +250 @@
                         }
 
                         this.typing = true;
+                        this.lastKeystroke = keystroke;
                 },
 
                 fireChange : function()