How to fix Ctrl+- keyboard shortcut to zoom out?

I'm using Ubuntu 21.04. The Ctrl+- keyboard shortcut for zooming out doesn't work in any app (Terminal, browser, etc). The Ctrl++ and Ctrl+0 shortcuts work fine, and I can zoom out by clicking the menu buttons with a mouse, and those menu buttons have a label that says Ctrl+-. I've checked my keyboard shortcuts in system settings, and there is nothing else assigned there using - or mentioning zoom. I can create a custom shortcut, and when it asks me to press the keys to assign the shortcut, it recognizes Ctrl+-. What else can I check to figure out if there is some shortcut conflict or other reason that the Ctrl+- shortcut is not working.

Solution 1:

It turns out that the problem was in Settings, under "Region & Language", I had selected a non-US English version for "Language". Even though my keyboard layout was set to US English, it seems that Ubuntu was using a different layout for keyboard shortcuts. Changing the "Language" setting to match my physical keyboard layout fixed the problem, but is less than ideal, since I'd like to have a different "Language" setting for other scenarios.