Click or press Ctrl+Z when is selected, or select Vector Edit Menu > Undo.

Undo undoes up to 256 vector edits.

You cannot undo the following vector edits:

Write vector text when the Vector Outline option is selected.

Edit a vector text string when the Vector Outline option is selected.

Edit a vector text character when Display Mode is set to Chars.

Make all vector text the same height using Unify String Heights.

You cannot undo the following vector edits. In addition, when you use them any pending vector undos will be lost:

Split polylines into lines and arcs using Un-Make Polylines.

Join lines and arcs into polylines using Make Polylines.

Change vector colors to the color of the raster image beneath using Vector Colors to Raster Colors.