why my treeview window appeared on the left top corner of window

[joyo]

Hi,

I have a form which contains a tab control. In the pages,
I used treeview, but I don't know why it shows on the left
top coner of screen when I first time to enter the page. I
just need to switch to other page and come back. It is
back to normal.

What is the problem?

Thank you very much.

joyo