>>Now this will be a combination...
>>
>>I have a desktop form (_Screen invisible), from which I call a modal, read_only form which has only a display grid. It has no objects to receive focus, it simply displays it and reacts upon Form.KeyPress. It worked like a charm, until I made some changes on WindowState, WindowType, Desktop and such... now this inner modal form behaves as if it weren't modal: it flashes a little, and goes out.
>>
>>In the debugger I've discovered that after CreateObject()ing and Show()ing that form, the code continues running, as if it wasn't modal. Any idea of where should I look at?

>Are you sure WindowType is set to Modal?
>

It was, but I've put it to be WindowState=2 (as Top-level), and WindowType automatically reverted to 0 (modeless). It didn't disappear, though, it was behind the first window :). See reply to George for details.