undo/redo
Most changes made within the lighttable are recorded and can be reverted to a previous state. This includes modifications to color labels, ratings, geo-localization, tags, metadata, orientation, copy/paste of history, image duplication, or application of a style. Note that the facility to undo/redo actions is unlimited in the number of steps while in the lighttable view, but it is reset each time you switch to a different view.
Press Ctrl+Z to undo the last modification and Ctrl+Y to redo the last undone modification (if any).