Treeview shows up wrong position

[joyo]

I put a treeview control in a Tab page, but when I want to
display this treeview, it shows up at top-left of form one
time. I have to switch pages, then the display is back to
normal. In addition, how to clean up a treeview. When I
selected different item, go to treeview. All new data just
appened to the old data. I would like to remove the old
data, just display the new data.

Thanks

joyo