>>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!?

I think because the form moves off the viewable area and back before you notice it. that's just a SWAG, however. The problem you may be finding with my method is that you may not be finding the correct window handle. I think Crhistof Lange may have mentioned that a call to GetDesktopWindow() may work in these situations. I haven't tested it, though.