The eraser: It is used to delete guidelines (rub them out permanently). If this environment-friendly guideline feature is switched on, every click on a guideline will remove it for ever. However this only applies to guidelines that were set by the functions described above. Frame guidelines (see below) and grid lines (also see below) can only be deleted by an explicit redefinition (with the value zero). To delete all guidelines you can also use the function described below.