1. Please test with zktest/test2/B30-1852304.zul
2. Please mouse over X, then Y, and click upon the Y, you should see the popup component is shown.
But sometimes the popup won't show if the mouse-over effect doesn't show on the menuitem for IE6.
The issue looks like if the cursor is moving close to the middle separator, the mouse-over effect on the menuitem won't show up.