When I open Firefox for the first time, the few addons I have in my overflow menu can open and work fine. However after a short time of having it open, they seem to stop functioning. Example is the uBlock addon that I have installed. When I click the icon for it while it's in the overflow menu, it just closes the overflow menu and nothing opens. If I try the same with my password manager, the same problem occurs.

I can drag the icon back to the toolbar and then it works fine, but if I drop it right back into the overflow menu, it doesn't work until I restart the browser. Any ideas?