Hi, so I'm having issues with my Wacom tablet and photoshop. When I'm drawing and I need to undo (i have the key command set on my pen) it doesn't undo at all, but if I draw some more then the undo on the pen works. Also, when trying to zoom in or move the screen using the tablet it doesn't do anything at all until I use my computer mouse and click on the photoshop screen then photoshop goes crazy with the zooming in and moving I tried to do before. How can I fix this problem