Index: /CKEditor/branches/prototype/_source/plugins/flash/dialogs/flash.js
===================================================================
--- /CKEditor/branches/prototype/_source/plugins/flash/dialogs/flash.js	(revision 2827)
+++ /CKEditor/branches/prototype/_source/plugins/flash/dialogs/flash.js	(revision 2828)
@@ -27,4 +27,5 @@
 	var uploadAction = 'nowhere.php';
 	var regexSize = /^\s*(\d+)((px)|\%)?\s*$/i;
+	var regexValidSize = /^(\d+)\%?$|^$/i;
 
 	var previewAreaHtml = '<div>' + CKEDITOR.tools.htmlEncode( editor.lang.dlgImgPreview ) +'<br>'+
@@ -393,9 +394,7 @@
 								validate: function()
 								{
-									var aMatch  =  this.getValue().match( regexSize );
-									if ( this.getValue() != '' && aMatch )
+									var aMatch  =  this.getValue().match( regexValidSize );
+									if ( aMatch )
 									{
-										if ( aMatch[2] == '%' )
-											aMatch[1] += '%';
 										addChange( 'width', this );
 										return true;
@@ -414,9 +413,7 @@
 								validate: function()
 								{
-									var aMatch  =  this.getValue().match( regexSize );
-									if ( this.getValue() != '' && aMatch )
+									var aMatch  =  this.getValue().match( regexValidSize );
+									if ( aMatch )
 									{
-										if ( aMatch[2] == '%' )
-											aMatch[1] += '%';
 										addChange( 'height', this );
 										return true;