When I have an image/picture selected in MS Word 2016, hitting SHIFT+F10,A opens up the Alt text dialog (for lack of a better term, it's now shown in a column to the right of the document itself, not a free floating dialog box) and places me in the edit box for the Alt Text for that image.
Hitting ESC after I've completed whatever text I want throws focus back into the document, but does not close that dialog. But its presence really doesn't matter, as it's not showing anything unless you happen to have a picture selected.
Brian - Windows 10 Pro, 64-Bit, Version 1909, Build 18363
Tolerance is the positive and cordial effort to understand another's beliefs, practices, and habits without necessarily sharing or accepting them.
~ Joshua Liebman