CKEditor 4.3.1 fillEmptyBlocks Doesn't Seem to Work

Hi everyone.

Having spent quite some time searching around to stop CKEditor adding &nbsp; into empty <div>'s.  I have added the following into ckeditor > config.js but still the &nbsp; is being added...

CKEDITOR.editorConfig = function( config ) {
	// Define changes to default configuration here. For example:
	// config.language = 'fr';
	// config.uiColor = '#AADC6E';
	       
	        config.fillEmptyBlocks = false;       
	
	        // Prevent filler node only in float cleaners.
	        config.fillEmptyBlocks = function( element )
	        {
	                alert('fillEmptyBlocks!');
	                if ( element.attributes[ 'class' ].indexOf ( 'clear-both' ) != -1 )
	                        return false;
	        }
};

...and as you can see from the attached screen shot, it's still adding the &nbsp;

Any help would be much appreciated.