Kdenlive/Manual/Edit Menu/Undo
Edit Menu - Undo
Ctrl + Z.
is used to reverse the last change you made or operation you performed in Kdenlive. If you have made multiple changes to your project, Undo can be used repeatedly to rollback each of the changes in the reverse order they were performed. Undo can also be executed from the icon on the Extra Toolbar ( ) or by using the keyboard shortcut