Hi. Sure. The application is called Codebook (a password vault). I don't know exactly how this is handled, but here's how it works: A component of the software (Codebook) called "Secret Agent" is running in the background and listening to the keyboard entries. When the shortcut (which has been previously configured in Codebook) is detected (in this case with Firefox as active window, e.g. when a password needs to be introduced on a web site), the "Secret Agent" window pops up and (after entering the master password), allows you to search for the corresponding password. Once the corresponding password (or other entry) has been selected, you hit "enter" and the password is handed over to the software running in the active window (Firefox browser, in this case) and is introduced into the space where the cursor was located when the shortcut was pressed. This has always worked without issues on the Firefox side, but since some time (as mentioned, can't tell exactly from what FF version on), Firefox captures the shortcut and "reacts" by zooming out. Secret Agent still works (the window pops up as expected), but the point is that BOTH software (Secret Agent AND Firefox) are acting on the shortcut, while in my humble opinion FF shouldn't do it (at least not by zooming out), as the shortcut for zooming out in FF is already defined as CTRL+"-". So if it reacts to BOTH, CTRL+"-" AND SHIFT+CTRL+"-", Firefox is using two shortcuts for the same thing, which isn't the idea of shortcuts (at least from my point of view). Of course I can configure something else in Codebook, but as FF didn't show this behaviour before and two shortcuts for the same function are rather unusual (shortcuts are limited and should be used in a unique way by definition), I wanted to make aware of this situation.