SetWindowPos - Topmost form won't stay topmost?

I have a VB application, notably Freebar, which has a setting to keep it "always on top". The code for this setting is as follows:
 

 SetWindowPos Me.hWnd, IIf(GetValueFromINI(SETTINGS_INI_SECTION, "OnTop", SettingsINI, DEFAULT_ONTOP) = "1", HWND_TOPMOST, HWND_NOTOPMOST), 0, 0, 0, 0, SWP_NOMOVE + SWP_NOSIZE
 

 
The setting seems to work for the most part. However, it stops working periodically throughout the day - specifically, when I receive an incoming call on Apropos (I HATE that program).
 
So my question is - why doesn't Freebar stay on top? Apropos is NOT configured to be "always on top", but it does steal focus when a call comes in (even with TweakUI installed and registry tweaked). I'm wondering if one application is "topmost" and another application comes along and sets itself as "topmost", what happens to the first application? My theory is that the Apropos developers used the topmost option as a way to steal focus while circumventing Windows' settings. I have tested with Windows Task Manager set to "always on top" and when Apropos rings, task manager loses its topmost position.
 
Does anybody have any ideas on how I could work around this? I can modify the source code for Freebar if there's a change I can make that will get it to stay always on top.

I think that you probably have it right and there won't be much that you can do. I would suggest complaining to Apropos. I suppose it is possible that you could have a service running that listens for an event to fire that represents a change in the windows z-order. I'm not positive that there is such an event but therer may be.

I've been considering modifying the source code of Freebar to periodically reset itself as topmost. I'd need to implement a loop or some sort of listener that is guaranteed to go off every 60 (or 300?) seconds and I'm not sure how to go about doing that. A listener would be preferable for performance but what event would I listen for?

Like I said, I'm not even positive that there is one.

I was thinking of an event listener notified by the system clock every few minutes. I'm searching for how to implement a clock listener in vb but so far haven't found anything.
 
:edit:
I found this page (FINALLY) http://support.microsoft.com/kb/231298 which explains how to use a waitable timer in VB. Now the question is will that timer make the applicaton unresponsive when it's running - should I put that in a separate thread in the application?
 
... I can already see it coming - I'm going to have to teach myself threading in VB while teaching myself VB... with no IDE.