I posted this earlier in the framework.windowsforms newsgroup, but in light
of our deadline and the fact that this is very likely a performance-related
issue, I'm looking for clues here as to what may be possible causes for slow
window dragging. Our app is a skinned app, and until recently had no issues
being dragged around the screen. We've used any number of methods for
dragging (currently using SendMessage(handle, WM_NCLBUTTONDOWN, NTCAPTION,
0)) but since all methods show the same problem, we're sure the cause is
unrelated. On some machines dragging the app around is completely normal, on
others it's extremely slow, though sometimes, if left sitting, it suddenly
drags normally, as if garbage collection did it's thing and set things back
to normal.
Additionally, if the app is, for example, dragged to the bottom of the
screen so much that only the top 40% or so is visible, dragging is at normal
speed so long as the percentage of the app that is visible doesn't increase
above that 40%.

Given that, is anyone aware of any .net vulnerabilities, or typical coding
mistakes, that we should focus on to get past this?
(fwiw- all the app's CreateGraphics are indeed followed by Dispose()).

Thanks much,
Eddie