Outside of any command, clicking on a visible physical property string allows the property to be edited. The property string must be close to or overlap the object. If the string is too far away from the object (if there are a large number of properties, or the object size is small) it can not be selected in this way. The user is first prompted for new text, then for a new property number. The clicked-on property will be replaced with the new values. If Ctrl-D is pressed at any time while responding to the prompts, the property will be deleted, with no replacement.
Properties numbered 7000-7104 are not displayed. These numbers are reserved for internal use should not be assigned.
If the variable EraseBehindProps is set (with the !set command), then the background behind the property strings is erased. This improves visibility of the strings.