“Un-does” the last action you performed while making a change to an opened image. You can click Undo to reverse up to 10 recent changes to your image.
Example: If you changed a color and do not like the result, select Undo to “go back” to the previous color version, or continue undoing up to 10 changes.
Undo is also one of the default tools shown in the Quick Access toolbar at the top of the ribbon. This allows you to use this function wherever you are working in HyperSnap.