[perl-win32-gui-users] Changing a the topmost Window property

[Guillem Cunillera Wefers]

I would like to change the property "topmost" of a Window which is declared 
with -topmost =>1

I have tried this two sentences:

$WindowVis->Change($WindowVis, -topmost =>0);
$WindowVis->Change(-topmost =>0);

but no results...

What's wrong ?

Guilem