XTREE checkbox enhancement: New special PopupMenu actions have been implemented to allow access to the set all (^A), clear all (^B) set all dependents of current item, clear all dependents of current item, and undo (^Z) functions: $CBSET, $CBRST, $CBSETDEP, $CBRSTDEP and $CBUNDO. These may be added to individual column menus, or to the common (column zero) menu. In either case, they will only appear when an extended checkbox column (T+) is right-clicked. Furthermore, the undo option will only be enabled when undo is possible. For example:
Coldef = "0~0~x~H~PopupMenu=Set All,$CBSET;Clear All,$CBRST;" "Set all dependents,$CBSETDEP;Clear all dependents;$CBRSTDEP;" "Undo;$CBUNDO~~"
The above would create a common popup menu with the specified functions which would only appear in the context of an extended checkbox column.
Note that if XTF_MLVL is not set (i.e. tree is not multi-level), the $CBxxxDEP options will be ignored. If multi-level, but the clicked-on item doesn't have dependents, then the option will be disabled.
