If I press the space bar and click and drag with the touch pad mouse built into my laptop, it zooms instead of panning. If I hold down the space bar and try to pan using my art tablet, the first click pans but all clicks after are the brush tool not the pan tool. This makes Krita usable because as I try to pan across the canvas while zoomed in, I draw random lines instead of moving over bit by bit. The current tool needs to stay the pan tool until I release the spacebar.
Well, I don't have a Mac to test, but which version of Krita are you using?
Krita version 3.3.0. I just started trying to use Krita to see what I think of it, though honestly this issue is making it super annoying to try to move around a document. Well this and the zoom tool. There's no way to add a keyboard shortcut to the zoom tool itself, just for the commands zoom in/out/to 100%. Meaning I have to select it in the tools panel to use it at all / ever (which is just not how I do things when I art; I keep one hand holding the tablet pen and the other on the keyboard for all the shortcuts).
As I've been using Krita, I've notice it's not just the space bar. For example holding down cmd with the brush tool to get the eye dropper stops working after a single click as well. I really hope this might get fixed soon, it kinda makes the program useless :( which makes me sad because the brush is so nice to use and I really want to just go nuts, fall back on all my usual habits, and just have fun painting.
I've researched this bug. You can find reports here: https://www.reddit.com/r/krita/comments/5fvy3q/shortcuts_randomly_not_working_mac/ and also here: https://bugs.kde.org/show_bug.cgi?id=381067 The source of your problem with the shortcut keys is the command key. I found the pattern after messing around for a little bit and noticed that shortcut keys weren't working after I used any shortcut with the command key. You will have to reassign any combination keys with another modifier key. I chose to use the control key since it's similar to a windows computer anyway. You don't have to reassign every single shortcut with the command key. Just reassign the ones that you need. However, the funny thing is that the color picker seems to work fine for me, so I left it alone. The other interesting thing is if I switch to another app and come back to Krita, it seems to work again. Good luck. Don't give up on Krita. It's a good program. I'm not sure if this bug is related, but: https://bugs.kde.org/show_bug.cgi?id=379576
I'm sorry, but I cannot reproduce this issue on my mac. Pressing space, then click-drag with the touchpad pans the image...
*** This bug has been marked as a duplicate of bug 383911 ***