>My Obj2Bmp utility, locks a treeview using the LockWindowUpdate() in Win32. You might want to take a look at that to see how I do that. The treeview (which is sub-classed) has a custom property which holds its window handle. The Refresh button has the declaration and code.

Looks good, but i cheked and don't works, maybe I extracted the code badly, i must revise this, but the suggestion of Jose Constant works! incredible i couldn't believe it, see:

thisform.mytreeview.left = thisform.mytreeview.left - 1000
..
...
stuff
...
..
thisform.mytreeview.left = thisform.mytreeview.left + 1000

I do not understand why this works!?