Specifies formatting string for the group name.
property GroupFmt: ecString;
GroupFmt is used to form text range's group name that is used in TSyntaxTreeView. If GroupFmt is empty, there is no group for this text range.
If text ranges within one parent have identical group name, Group node will be created with caption of this group name and all these text ranges will be children of this group node.
See Name formatting (for block rules) to understand principles of building names format.