how to check the widget is really visible or not ?

[KC <kcc1967 gmail com>]

Hi,

I did a very simple test (see attachment).
Create a window and add a timeout callback to check if the
window is visible.

When I run the example, the window popup and callback will
print "win ...... VISIBLE", so far so good.

Then, I deiconify the window; move the window to other desktop workspace;
use other application to cover the window completely ....
No matter what I do, I still got the window is visible !!!!

What's wrong with my code ?  Thanks a lot.

Regards
KC