Oracle Forms

Hi,

I'm calling a second form (FORM_B) from within another form (FORM_A) using open_form.
When I now try to close FORM_B using the little X-Button on the upper right corner of the window nothing happens. The when-window-closed trigger does not fire.
When I try to close FORM_A in the same way, the trigger fires - it works fine.
Also when I open FORM_B directly (without open_form) and try to close it, the trigger fires... Just not when the form is called from the other form...

Can anyone tell my why the trigger doesn't fire?

Greetings,
kaba