Not all the actions performed can be undone or redone. If an operation does not
support undo/redo, the undo/redo functionality will be disabled once the action is
completed and any previous undo/redo history recorded will be reset. The undo/redo
history will also be reset every time a macro or other tcl application is
invoked.
Note: The undo/redo functionality is supported by most panels,
tools and user interface functionalities.
By default, the number of undo actions is set to 100 and the maximum undo memory (MB)
is set to 2500. You can modify both of these settings by going to File > Preferences > Performance.
Undo/redo history may use a large amount of memory. By default, a threshold of 80% of
the total memory limit will not be exceeded. Once the memory threshold is exceeded,
all older actions will be automatically purged.
Undo an action by clicking Edit > Undo from the menu bar, or pressing
Ctrl+Z.
Redo an action by clicking Edit > Redo from the menu bar, or pressing
Ctrl+Y.
Tip: Simultaneous actions can be undone/redone by selecting them from the
Undo/Redo menus on the menu bar. Figure 1.
