Merge branch 't/10879' into major

CHANGES.md

@@ -15,6 +15,7 @@ Fixed Issues:
 * [#10835](http://dev.ckeditor.com/ticket/10835): [Enhanced Image](http://ckeditor.com/addon/image2): Improved visibility of the resize handle.
 * [#10836](http://dev.ckeditor.com/ticket/10836): [Enhanced Image](http://ckeditor.com/addon/image2): Preserve custom mouse cursor while resizing the image.
 * [#10881](http://dev.ckeditor.com/ticket/10881): Various improvements to *Enter* key behaviour in nested editables.
+* [#10879](http://dev.ckeditor.com/ticket/10879): Remove format should not leak from nested editable.
 
 ## CKEditor 4.3 Beta
 

core/dom/range.js

@@ -982,6 +982,9 @@ CKEDITOR.dom.range = function( root ) {
 							enlargeable = container;
 					}
 
+					// Ensures that enlargeable can be indeed enlarged, if not it will be nulled.
+					enlargeable = getValidEnlargeable( enlargeable );
+
 					while ( enlargeable || sibling ) {
 						if ( enlargeable && !sibling ) {
 							// If we reached the common ancestor, mark the flag
@@ -1094,7 +1097,7 @@ CKEDITOR.dom.range = function( root ) {
 						}
 
 						if ( enlargeable )
-							enlargeable = enlargeable.getParent();
+							enlargeable = getValidEnlargeable( enlargeable.getParent() );
 					}
 
 					// Process the end boundary. This is basically the same
@@ -1225,7 +1228,7 @@ CKEDITOR.dom.range = function( root ) {
 						}
 
 						if ( enlargeable )
-							enlargeable = enlargeable.getParent();
+							enlargeable = getValidEnlargeable( enlargeable.getParent() );
 					}
 
 					// If the common ancestor can be enlarged by both boundaries, then include it also.
@@ -1321,6 +1324,13 @@ CKEDITOR.dom.range = function( root ) {
 					if ( tailBr )
 						this.setEndAfter( tailBr );
 			}
+
+			// Ensures that returned element can be enlarged by selection, null otherwise.
+			// @param {CKEDITOR.dom.element} enlargeable
+			// @returns {CKEDITOR.dom.element/null}
+			function getValidEnlargeable( enlargeable ) {
+				return enlargeable && enlargeable.type == CKEDITOR.NODE_ELEMENT && enlargeable.hasAttribute( 'contenteditable' ) ? null : enlargeable;
+			}
 		},
 
 		/**