Ctrl+Z ruins workflow

Hello, 

I am illustrating and coloring comic panels. I end up with many layers as I go, and I don't lock them because I'm frequently bouncing between them to touch things up. Illustrating requires drawing quick lines, and undoing those lines when they're not right, so I'm using ctrl+z a lot.

Problem is, a little more than a third of the time, using ctrl+z changes my tool from "brush" to "move". Meaning when I mean to draw a quick line on one layer, instead I'm now moving an element from a different layer. 

Now I have to stop what I'm doing, undo the move, find the layer I need to draw on, and select the brush tool again. It's not a huge time cost but jfc it completely derails my workflow and causes needless stress. To add insult to injury, normally control isn't a permanent tool change, it temporarily allows you to move something. But somehow adding the z turns it into a permanent tool change which I did not want or ask for. And I can't find a way to stop control from being the hot key for the move tool. 

PLEASE GOD CAN YOU FIX THIS UNGODLY IRRITATING BUG?! I AM BEGGING YOU.