With photoshop open, but minimized, holding ALT and pressing any number on the top row (1 thru 0) does not register in other applications at an operating-system level. Using the on-screen keyboard in Windows doesn't bypass this, even.
This has been an issue for many, many years. Since Windows 7/whatever version of Photoshop then (CS3? CS5? idk)
Super annoying to have to leave Photoshop maximized or close it in order to use irssi or finch in a terminal window elsewhere, or anywhere else alt+number is a shortcut for something.
Here's a report of the issue elsewhere from 2013 --