SpiderBasic

I often use iFrames to integrate Spiderbasic webapps into a website.
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?

There could be several events fired by the Accordion. What kind of accordion is this?

Unfortunately I have no idea what the accordion is built with. Possibly with dot net.
Here is the link to the page: https://tinyurl.com/y5fvphns