XTREE enhancement: add the ability to limit the Auto-Sum feature, introduced in 6.5.1631.0, to specific levels in a multi-level tree. As with the regular Auto-Sum feature, it is activated by inserting one of the following tokens into the header, or more typically, the footer part of the header:
=SUM ! standard auto-sum
=SUMLVL(#) ! auto-sum just level #
=SUMLVL(#,#,...#) ! auto-sum the specified levels
The last level in the parenthesized list may have a "+" appended to it, e.g. =SUMLVL(#,#+) indicating all of the levels from the specified one down. So for example, =SUM(0,2+) would include all levels except level 1.
This example includes levels 0, 1 and 2 in the Auto-Sum:
coldef += "20~10~Qty::=SUM(0,1,2)~#E~~
