Additional functions
Zoom
With the button
1:1 view 
the view is reset to
the standard zoom level.
With the
button 
the view is enlarged
in size.
With the
button 
the view is reduced
in size.
Undo actions
With the button
undo 
, you can undo the last 50
actions.
With the button
redo 
, the actions you have
undone before can be redone.