The RemoveLayer widget works with the SELECTED_LAYERS form variable, and deletes
this layer/these layers.

But after the execution it does not reset the form variable, which still has the
old value so the client thinks (at the javascript side) that there is still an
active layer.

Proposed fix to the ParseURL function:

..
			}
			$this->setVar('SELECTED_LAYERS', "");
		}
		return true;