Undo and Redo

All actions except grouping and ungrouping can be undone.  You can undo the last action by choosing Undo from the Edit menu or by typing Ctrl + Z.  You can redo the last undone action by choosing Redo from the Edit menu or by typing Ctrl + Y.

FX Draw's undo system is limited only by the available memory.  For most editing, you will not find the limits of the undo system and should be able to undo actions indefinitely.