Use this setting to define whether guides or guide points should be added to (Add) or subtracted from (Subtract) the existing guides or guide point selection, or if guides or guide points should be selected exclusively (New, all existing selections will be lost).
Use this setting to select the following guides or their complete guide points:
Inverts the selection. If, for example, you only want to select guide points that have been rooted too firmly. Simply select Unrooted in the Select setting and activate Invert.