Severe stack size problems in Windows build when menus are present

[Doug Lerner]

When I click on a button in my main stack it opens up a substack.

In OS X this substack looks fine. But in the Windows build it is really
weird. The stack ends up with a whole bunch of space ABOVE the menu, so the
controls below the menu are no longer visible.

It looks like a window with a file menu at the bottom, essentially.

If I remove the menu from the substack it sizes ok.

Any ideas about what might be happening?

Thanks,

Doug Lerner, Tokyo