Hi, in .NET 1.x you could try it from another thread and it might work (most of the time), or it could result in forms with a white menu bar on top (I'm sure you have seen these already, even on non-.NET code). in .NET 2.0 and up it gets rejected by default; you must set it up in such a way that all controls get handled completely by the thread that created them, often called "the UI thread" or "the main thread". For some simple examples, look at either one of my articles. :)
Luc Pattyn