Steps to Reproduce

open rod-grid-column-scroll-pos.zul
scroll down until ROD loads new rows
hide a column (using the column menu popup, or the debug buttons below the grid)

Current Result

scroll position changes to an incorrect position

Expected Result

scroll position should be preserved

Debug Info

after showing/hiding a column the scroll paddings tpad/bpad are reset to a 0 height.

Workaround

init the grid's scroll-paddings when changing the column visibility
(causes a short flickering in FF, edge - chrome looks stable)

	zk.afterLoad('zul.grid', function() {
		var xColumn = {};
		zk.override(zul.grid.Column.prototype, xColumn, {
			setVisible : function() {
				var result = xColumn.setVisible.apply(this, arguments);
				setTimeout(() => this.getGrid()._initPadSizes(), 0);
				return result;
			}
		});//zk.override
	});//zk.afterLoad