Win32 API: RealChildWindowFromPoint

BTW RealChildWindowFromPoint can't find controls nested in a GroupBox. It can only detect immidiate childs of the form. So if you click on Controls located in GroupBox the function will return the handle of the GroupBox.

I figured some things out. But it's a little more complex then it looks. The Forms doubleClick event doesn't respond to dubbelclicks or other clicks on other controls then itself. But I found a solution. I'm working on a library that should wrap some usefull functions. I'm developing the code files and test them in a form object. I inserted your function and played a bit with it. It works now so I want to provide you the project if you want. What for? Do you ask. Why give the whole project? I've got the most usefull functions of the windows message queue implemented. Armed with the MessageQueue you can respond to DoubleClicks and other mouse events from everywhere. So you need that Queue to use the RealChildWindowFromPoint function properly. If you are interested just click on my nickname and mail me. If you mail me I will comment the code and share this solution with you, ok? Cheers

Look at this page: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui/windowsuserinterface/windowing/windows/windowreference/windowfunctions/realchildwindowfrompoint.asp this is the C# implementation of the function: [DllImport("user32.dll")] public static extern IntPtr RealChildWindowFromPoint(IntPtr hwndParent, POINT ptParentClientCoords); I tried to make it work. But in this few minutes I can't really get a good grasp on how to use it. The only thing I do know for sure is that the function returns an IntPtr of the control clicked. You can check for a valid control like this: IntPtr ptr = Windows.RealChildWindowFromPoint(form.Handle ,msg.pt); Control ctrl = Control.FromHandle(ptr); if(ctrl != null) { //do something }