[GD-Windows] Hijacking application

[Brian H. <ho...@py...>]

I have a feeling this can't be done, but I figured I'd ask the list 
anyways just in case.

Say I want to write a plug-in for random application XYZ.  XYZ, 
however, may not have a plug-in API or it may be broken.  Use Notepad 
as an example.

If I wanted to add a plug-in, it seems like it would be pretty much 
impossible unless my plug-in didn't require any of the application's 
other data.  

I swore there were a few plug-ins I've seen that have forced their way 
into an application, but I can't think of what they might be now.  The 
obvious ones are like Visual Assist, Max plug-ins, Maya plug-ins, 
Photoshop plug-ins, VS plug-ins, etc. but those all have registered 
APIs.  I've seen screenshots of people that have retrofitted a new 
menu into Notepad just to prove it can be done, but I'm not sure what 
the point of that is.

The typical way you do this is a pretty convoluted process involving 
subclassing and message hooks, but even then you can only trap new 
menu items and maybe a couple of key messages like WM_DESTROY.  You 
obviously can't grab application data and do anything meaningful with 
it.

Brian