Setting window.alwaysOnTop has no effect in a Web Extension bg script

I would like to create a window that is “always on top”. I see a Window.alwaysOnTop property documented here: https://developer.mozilla.org/en-US/Add-ons/WebExtensions/API/windows/Window. It does not seem to be supported as a WindowCreateOption (get an exception in the debugger) and setting it programmatically in the create window callback seems to have no effect. Is this property not supported or is there some other way to set it?

Thanks!
Scott

I recall this only had affect on windows and it was not guranteed to work. It did not work for me in linux or macs, in my last test (a year ago). Is this the same experience you had?

Personally - I had to use js-ctypes to acheive the always on top. There was no other way. If you use this though, you can’t do it from a WebExtension. - https://addons.mozilla.org/en-US/firefox/addon/topick/

But hang in there, maybe someone here knows of a webext compatible way.

This addon seems to have some on top behavior -
https://addons.mozilla.org/en-US/firefox/addon/tab-notifier/

@noitidart thanks for your response. I have not tried on win/linux yet, only MacOS and yes, same experience there. Does not seem to do anything.

I’ve a feeling this is supposed to be read-only. The documentation doesn’t make it clear, but there is nothing in the definition of this property that would be intended to make it a setter, only a getter. It is simply defined to be a boolean comparison between two properties of the actual window object.