The question:
When I quit the modeless dialog, I display, during the Queryclose method, a textbox warning with SELF as Owner : Great : The Textbox is modal for the modeless dialog but NOT for the TopAppWindow !?!?
Possible Error :
I can reach some items in the menu (or toolbar) and an error could happen...
The answer:
Textbox uses the normal Windows MessageBox. You can set styles to make it System Modal or AppModal:
MB_APPLMODAL
MB_SYSTEMMODAL
MB_TASKMODAL