Originally posted by Fzanco:

Originally posted by RequiemsRose:

You can split stacks. Hold shift when clicking the stack to bring up the option to split it. Hold ctrl when clicking to auto-transfer the entire stack.

is there an option to remove one from a stack, I swear I did this once by accident

Yeah, when you hold shift to split the stack it brings up a slider. By default it sits at roughly half the stack size but you can slide it either way to select exactly how many you'd like to take.