Attempted to split a stack with Shift + Right Click, and it popped up a window to split the stack, but wouldn't do anything after that. Just had a black box with the split stack, and a slider I could move around. This affects the bottom row only. as it spawns the box too low to hit confirm or cancel
Could not do anything to get the box to go away. even after closing inventory, the box remains. Changing locations just has the box behind my little calendar cycle in the bottom right corner, but it did make it go away from my inventory screen.