How to undo and redo
Undo the last action by pressing Ctrl+Z (Windows/Linux) or ⌘+Z (Mac). Each press steps one action further back.
Redo to restore an undone action by pressing Ctrl+Y or Ctrl+Shift+Z . Each press steps one action forward again.
Or use the toolbar buttons. Click the Undo (⤴) or Redo (⤵) arrows in the toolbar for the same effect.
Continue editing. Once you undo and then make a new change, the redo history for that branch is cleared — just like all standard applications.
How the history works
Step-by-step
Each drawing action (pencil stroke, shape, fill, move, etc.) is recorded as a separate step. Undo steps through them one at a time.
History limit
The history keeps up to 50 steps by default. Actions older than that cannot be recovered.
Branch clearing
If you undo several steps and then draw something new, the redo history after that point is cleared. This is standard behaviour.
Tips
Do not be afraid to experiment! Undo is always available to reverse any mistake instantly. Try bold effects and undo if they do not work.
If you are about to try something risky, save your work first (Ctrl+S). That way you have a fallback beyond the undo history.
Hold Ctrl and press Z repeatedly to step back through multiple actions quickly.