So I recently downloaded the newest version of Krita, and have discovered something a bit weird. Whenever I use the grow or shrink selection tools, it will only change the dimensions from the sides, not from the top and the bottom of the selection. Am I missing something, or it just not working? I've attatched some images of what happens when I try to grow/shrink after selecting a black square.

You are correct, Krita wasn't working properly, it was as bug. the good news is that it is now fixed and the fix should be available when the next version of krita comes out.

Thanks!