Steps to Reproduce

run the attachment empty-listbox-with-hidden-column.zul
compare the positions/sizes of the empty messages

Current Result

depending on which columns are invisible the size and position varies between different listboxes, if the first column is invisible the message even line breaks

Expected Result

empty message cell should span over all columns to have the whole table width available for an "empty-message"

Debug Info

the colspan attribute is calculated incorrectly - ignoring invisible columns

Root Cause

https://github.com/zkoss/zk/blob/44033b6a35d00482dd9c47ef724f167c4768b252/zul/src/archive/web/js/zul/sel/Listbox.js#L33

Workaround

currently commented out in empty-listbox-with-hidden-column.zul

	zk.afterLoad('zul.sel', function() {
		var xListbox = {};
		zk.override(zul.sel.Listbox.prototype, xListbox, {
			bind_ : function(desktop, skipper, after) {
				var result = xListbox.bind_.apply(this, arguments);
				var wgt = this;
				after.push(function() {
					if(wgt.listhead) {
						wgt.$n('empty').colSpan = wgt.listhead.nChildren;
					}
				});
			}
		});//zk.override
	});//zk.afterLoad