[Qt-interest] Mouse movement required to make things happen?

[Bob Hood]

We're seeing a rather strange behavior (Qt 4.6.1 Windows Vista 64-bit,
and verified to also happen with 4.6.2).  We're seeing action initiated
by the user (from the GUI) requiring the mouse to move before they
begin.  For example, I have a window that animates as an overlay onto
the main interface, and I do this using a timer to move it manually. 
When I activate the code by selecting a menu item from the main
interface, if the mouse remains perfectly still, the window will not
appear.  It is only after I move the mouse at least one pixel in any
direction that the mechanism activates, and the window pops into view.

Note that I've also tried using QPropertyAnimation, and I have the same
problem after start()'ing it.  The mouse has to move at least one pixel
before the animation will commence.

Anybody have any clues as to why this weird Qt behavior is occurring,
and how to make it stop?