[RESOLVED] Postmessage - x,y coordinates wrong (MakeDWord)

[Krass]

(I had another thread dealing with my current problem - but my needs evolved so I think a new thread couldn't hurt - also helping me to reach more people)

Here's the code I use. PostMessage sends a click on my vb-form, and the Form_MouseDown reacts to it by msgbox'ing the coordinates.

Private Sub Form_MouseDown(Button As Integer, Shift As Integer, X As Single, y As Single)
    MsgBox "x: " & X & " y: " & y
End Sub

Private Sub Command2_Click()    
        Call PostMessage(Me.hwnd, WM_LBUTTONDOWN, 0&, MakeDWord(200, 200))
        Call PostMessage(Me.hwnd, WM_LBUTTONUP, 0&, 0&)
End Sub

When clicking Command2, the Form_MouseDown even *IS* fired, but always white those coords: x: -45600 y:285. No matter what value I send to MakeDWord, I end up with -45600,285.

Private Declare Function PostMessage& Lib "user32" Alias "PostMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any)

Function MakeDWord(LoWord As Integer, HiWord As Integer) As Long
    MakeDWord = (HiWord * &H10000) Or (LoWord And &HFFFF&)
End Function

...Am I missing something here?

Using winspector, I've been spying on the form. Here are the results:

When manually cliking the form:

WM_LBUTTONDOWN - Mouse coordinates:  325,184
WM_LBUTTONDOWN - Mouse coordinates:  325,184, Button pressed:  MK_LBUTTON
WM_LBUTTONUP - wParam:  0x00000001, lParam: 0x00b80145
WM_LBUTTONUP - wParam:  0x00000000, lParam: 0x00b80145

when using Command2_Click

WM_LBUTTONDOWN - Mouse coordinates:  -3200, 19
WM_LBUTTONDOWN - Mouse coordinates:  -3200, 19
WM_LBUTTONUP - wParam:  0x00000000, lParam: 0x0013f380
WM_LBUTTONUP - wParam:  0x00000000, lParam: 0x0013f380

Even tho the 2nd solution shows -3200, 19, the msgbox still shows "-45600,285" - OH, actually I just noticed the msgbox now shows "-48000,285" (I think those numbers changed because I've closed and rerunned my VB app).

Odd.

Any feedback VERY welcome.

(Edit: I did try SendMessage instead, ending up with the same results)