Here is the bug.

Setup
#1. You have a window open.
#2. You have two toolbars each on a different row

Action
#3. You move the bottom toolbar up to the top row (you can do this manualy or programaticaly.
#4. Click and drag the form just under its title bar somewhere, or double click just under the title bar. (you click in any area about as big as the title bar under the title bar).

Result
#5. The form will behave as if you had clicked on the title bar, aka it will drag around if you click drag and will maximize if you double click. This is especialy wierd if you have a normal control in that area of the form.

Anaylasis
I think that fox is not re-mapping the location of the controls when the form coords are adjusted after the toolbar is moved. This results in where you click not corrisponding to what you see (ofset by the height adjustment of the toolbar up top) This persists until you do something that causes Fox to "remap".

Help
I havn't found an unobtrusive way to get fox to remap the form and have it behave normaly. They user can do it by moving focus in the form to a control, but I can't get the same result programaticaly. Refresh/repaint didn't work, neither did wiggling the form.