PR
#2803 fix one of the biggest performance bugs in Leo's history.
The new code recalculates tree icons only for c.p and its direct parents. The old code recalculated icons for all visible nodes!!!
Yes, the new code handles cloned nodes correctly.
Please test devel and report any problems.
Edward
P.S. This fix merits a new version number: the next release will be Leo 6.7.
Edward