Deletes all locators (measurement, evaluation, and labeling objects) in the scene, with the possible exception of invisible locators or locators on reference layers.
When this option is checked on, only the active locators are deleted.
When this option is checked on (default), all invisible locators are protected from deletion.
This includes locators on invisible layers, invisible locators on visible layers, as well as locators attached to invisible objects (and therefore invisible).
When this option is checked on (default), locators on reference layers (layer state set to Reference) are protected from deletion.