Merge branch 't/10219'

Author: Reinmar

plugins/clipboard/plugin.js

@@ -480,7 +480,7 @@
 			// Use editor.document instead of editable in non-IEs for observing mouseup
 			// since editable won't fire the event if selection process started within
 			// iframe and ended out of the editor (#9851).
-			( CKEDITOR.env.ie ? editable : editor.document.getDocumentElement() ).on( 'mouseup', function() {
+			editable.attachListener( CKEDITOR.env.ie ? editable : editor.document.getDocumentElement(), 'mouseup', function() {
 				setTimeout( function() {
 					setToolbarStates();
 				}, 0 );