PRB: GetActiveWindow Behaves Differently Under Windows NT

MORE INFORMATION

Steps to Reproduce Behavior

1. Start a new project in Visual Basic. Form1 is created by default.
2. Add the following code to the General Declarations portion of Form1:

      Private Declare Function GetActiveWindow Lib "user32" () As Long
      Private Declare Function GetWindowTextA Lib "user32" (ByVal hwnd _
         As Long, ByVal lpString As String, ByVal aint As Long) As Long
      Private Declare Function GetForegroundWindow Lib "user32" () As Long
   
   						

3. Add a Command Button (Command1) to Form1.
4. Add the following code to the Command1_Click event:

      Dim myhwnd As Long
      Dim s As String
      Dim iret As Long
      Dim nullhwnd As Long
   
      s = Space(256)
   
      myhwnd = GetActiveWindow()
      iret = GetWindowTextA(myhwnd, s, 256)
      Debug.Print myhwnd, s
   
      Shell "Calc.exe", 1
   
      ' Wait for CALC.EXE to launch under Windows NT:
      DoEvents
   
      nullhwnd = GetActiveWindow()
      myhwnd = GetForegroundWindow()
   
      s = Space(256)
      iret = GetWindowTextA(nullhwnd, s, 256)
      Debug.Print nullhwnd, s
   
      s = Space(256)
      iret = GetWindowTextA(myhwnd, s, 256)
      Debug.Print myhwnd, s
   
   						

5. Press the F5 key to run the program. Click the Command1 button, and view the Debug Window. The first print statement will print Form1's hWnd and its Caption. The second print statement will merely print 0, because GetActiveWindow returns a null window handle. The third print statement will correctly print Calulator's hWnd and Caption.