unfortunatelly still i have some difficulties with the synhronization of
the Tree with Gantt:
1) as far as i've set lockHeaderOnVerticalScroll() to true, both
verticalscrolls of the Tree and Gantt do not function correctly, because
setTopItem()method doesn't take into account the size of Header...
2) strange, but with increasing number of rows in Tree/Gant - the rows are
not at the same level (synchronized) any more, but the difference between
them is growing also