<zk>
  <div>
    <drawer id="dr" closable="true" position="left" title="test">
      <div style="border: 1px solid red;" vflex="1">
        surrounding div uses vflex="1"
      </div>
    </drawer>
    <button onClick="dr.open()" label="open drawer"/>
  </div>
</zk>

<style>
.z-drawer-cave { height: 100%; }
</style>
<script>
var _xDrawer = {};
zk.afterLoad('zkmax.wgt', function () {
    zk.override(zkmax.wgt.Drawer.prototype, _xDrawer, {
        setVisible: function (visible) {
            _xDrawer.setVisible.apply(this, arguments);
            if (visible) zUtl.fireShown(this);
        }
    });
});
</script>