submenus will sometimes position off screen

[howudodat]

Describe the bug
I have a button at the top of the window with a drop menu. That dropmenu has another dropmenu. The submenu shows offscreen
One screenshot shows the issue, the other I added a bunch of seperators to show the full menu

To Reproduce
Put a menu with submenu and assign to a button at the top of the screen

Expected behavior
submenu should never go above top 0px

Screenshots

Sample Code

Menu<String> menuQB = Menu.<String>create()
	.setDropDirection(DropDirection.TOP_MIDDLE)
	;
Menu<String> menuInvoiceAll = Menu.<String>create()
	.setDropDirection(DropDirection.TOP_MIDDLE)
	;


for (JTPmtTerms pt : JTPmtTerms.GetAll()) {
	MenuItem<String> mi = MenuItem.<String>create(pt.toPickerString()).withValue(pt.id + "");
	menuInvoiceAll.appendChild(mi);
}


// default invoice type
menuQB.appendChild(MenuItem.<String>create(pt.toPickerString()).withValue(pt.id + "").appendChild(PrefixAddOn.of(Icons.new_box())));

// other menu options
menuQB.appendChild(MenuItem.<String>create("All Terms").setMenu(menuInvoiceAll));
menuQB.appendChild(Separator.create());
menuQB.appendChild(MenuItem.<String>create("Link Existing Invoice(s)").withValue("existing").appendChild(PrefixAddOn.of(Icons.link_variant())));
menuQB.appendChild(Separator.create());
menuQB.appendChild(MenuItem.<String>create("Re-Sync Invoice(s)").withValue("sync").appendChild(PrefixAddOn.of(Icons.sync())));