How to detect if window is open ?[resolved]

[Jmacp]

Well i know how to detect if an app is running by using its caption,

put this in a timer etc,

Dim WinWnd As Long
 WinWnd = FindWindow(vbNullString, "app caption")

but take the same app that has two different windows but both have the same caption, well you can identify sections(windows ?) within these windows by their handles.

So how would i code this to detect if a window is open by deteceting a certain part within this window by it handle...lol