Now I have an iFrame that is inside an accordion, that is folded up first.
Chrome, Opera and Edge render the iFrame (on page loading) correctly.
According to the debug, SpiderBasic can open a window in the size of the iFrame.
Only with FireFox it doesn't work. As long as the accordion is not unfolded, DesktopWidth() and DesktopHeigth() are zero.
So I use a timer to query the DesktopSize and create the window only when the accordion is unfolded.
But the problem is, that the box from CheckBoxGadgets() is not displayed.

On the left picture the representation is correct. On the right side you can see the errors.
Does anyone know this problem? What can I do?