Undo and Redo do not preserve the revision number of the object. For example, if an associative part dimension is created in the drawing, and you perform undo on dimension creation, the part and drawing are still considered modified.

Any command that changes the active model (this can be done with File > New, File > Open, File > Close Window, File > Erase > Current, File > Delete > [current], File > Exit, Window > Activate, Window > Close) clears the stack . However, these commands can still be invoked and not change the active model, and therefore will not clear the stack in that case. Such an example would be if multiple windows of the same drawing sheet were open, and Window > Activate was used to activate one of these windows.

Any command that changes both the active window and the current drawing page number will clear the stack.