Userscripts are not executed in popup windows in Firefox 148

[xstnztk]

I have a bit of a convoluted problem. I hope I can explain it correctly.

The website of my local public library uses pop-up windows to display some pieces of information. I want to process the information in such a pop-up window with a userscript, but only on demand because this processing takes a long time and causes lots of network traffic. I therefore used GM.registerMenuCommand (together with @grant GM.registerMenuCommand) to create entries in the Script Commands Firemonkey submenu which I can select to start the processing.

Unfortunately Firefox has not displayed the toolbar in pop-up windows for some time now, only the address bar. The Firemonkey icon is therefore not visible in pop-up windows, so I cannot click on it to choose the desired Script Command. I worked around the problem by setting browser.link.open_newwindow.restriction=0 in about:config to force the pop-up window to be displayed as a normal tab with the normal toolbar.

All this worked fine until recently. Today I noticed that the Script Commands submenu of this pop-up window is completely empty. Firemonkey still executes the userscript containing the GM.registerMenuCommand as far as I can tell, and it still shows a badge with "2" on the Firemonkey icon (because there are two matching userscripts for the URL).

I can only suspect that the recent update to Firefox 148 broke this because nothing else changed which could be relevant. Is there any way I can analyze this problem further to find out why the Script Commands list is empty for this pop-up window?

Thanks!

[xstnztk]

It seems my initial assumption was wrong and the userscript is not executed at all for the popup window. The popup window and the "normal" window it originates from share the same URL, so I added a check to distinguish between the two (by looking for a DOM element which is only present in the popup window), and console.log statements I added to the userscript are only triggered for the "normal" window, not the popup window.

So it seems that Firefox 148 changed something to not execute userscripts in popup windows. I therefore changed the title of this issue.

[xstnztk]

I converted my userscript to a proper Firefox addon (using an address bar button which is visible even in popup windows without any about:config hacks), so solving this problem is no longer a priority for me. You can close this issue if you want.