[vtkusers] vtk problems under linux

[tonywu at newsguy.com]

My development platform is Mandrake Linux and I have some problems using the
vtk:

1. If you stop cursor on a rendering object, the cursor will disappear after
the rendering. You can get the cursor back by moving the mouse but it will
leave a block (incorrect background) on the screen.

2. I try to development a full-screen application with a volume rendering
object and some menus. Since the volume rendering is a time consuming job, it
will also affect the performance of the menu displaying. Whenever you do a
Render(), all the objects on the screen need to be redraw. During this time,
all the UIs are locked up.

3. I try to create a 2D actor to replace the cursor. I works fine but then it
leads to the problem #2.

Any help is appreciated!