Holding rightmousebutton down

[Character]

I hope this is not a stupid question.
(forgive me if it is)

When holding down the rightmousebutton while pointing at the
titlebar of any program, (also IExplorer when loading a website
for example), will freeze the thing the program is doing at that
moment. When releasing the button again, the process continues
where it stopped.
When you use a (native) thread this does not happen.

My question is:
What is the cause of this? Does anybody know?

Netmaestro already helped me out by advising me another API
(http://www.purebasic.fr/english/viewtop ... highlight=)
but I am still wondering what the cause is. (thanks Netmaestro!)
Microsoft bug? Or API intentional?

Funny, I must have clicked on window-titlebars millions of times
but never noticed it...

[Num3]

ARghhh...

You've found the MS secret bug...

That's why they made Vista!!!!

[Fluid Byte]

You can stop the program from freezing by swallowing the #WM_NCRBUTTONDOWN message. You would have to manually handle the system menu though.