Any tool settings dialog should have a button to restore to the default values.

Moreover, that button should be available as a key-in to associate as a Function key as well.

This way if I use a tool a second time and I want the default parameters of the tool settings dialog I could press the function key to restore.

Due to "tool settings" dialogs always save the last change (enable/disable) or value then the next time I used the same tool I could restore to default quickly.