DOCUMENT:Q149487  11-JAN-2001  [vbwin]
TITLE   :BUG: Mouse Captured After Clicking DBGrid Column Header
PRODUCT :Microsoft Visual Basic for Windows
PROD/VER:4.0
OPER/SYS:
KEYWORDS:kbVBp400kbbuglist

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The information in this article applies to:

 - Microsoft Visual Basic Standard Edition, 32-bit, for Windows, version 4.0 
 - Microsoft Visual Basic Professional Edition, 16-bit, for Windows, version 4.0 
 - Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0 
 - Microsoft Visual Basic Enterprise Edition, 16-bit, for Windows, version 4.0 
 - Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0 
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SUMMARY
=======

Clicking a column header in a DBGrid control of a Visual Basic program causes
the mouse to remain inside the borders of the column headers. The program only
responds to keyboard commands when the mouse cursor is trapped in the column
header.

WORKAROUND
==========

In order to work around the problem it is possible to add the following code to
the project. Because this problem should not affect the compiled executable, it
is possible to remove the workaround before debugging.

1. Add the following code to the General Declaration section of the form:

         #If Win32 Then
         Private Declare Function GetWindowRect Lib "user32" _
         (ByVal hWnd As Long, lpRect As RECT) As Long
         Private Declare Function ClipCursor Lib "user32" (lpRect As Any) _
         As Long
         Private Declare Function GetDesktopWindow Lib "user32" () As Long
         
         Private Type RECT
             left As Long
             top As Long
             right As Long
             bottom As Long
         End Type
         
         #Else
         Private Declare Sub GetWindowRect Lib "user" _
         (ByVal hWnd As Integer,lpRect As RECT)
         Private Declare Sub ClipCursor Lib "user" (lpRect As Any)
         Private Declare Function GetDesktopHwnd Lib "user" () As Integer
         
         Private Type RECT
             left As Integer
             top As Integer
             right As Integer
             bottom As Integer
         End Type

2. Add the following code to the click event before the Stop:

         Dim winrect As RECT
         #If Win32 Then
             Dim dskhwnd As Long
             Dim suc As Long
             dskhwnd = GetDesktopWindow()
             suc = GetWindowRect(dskhwnd, winrect)
             suc = ClipCursor(winrect)
         #Else
             Dim dskhwnd As Integer
             Dim suc As Integer
             dskhwnd = GetDesktopHwnd()
             Call GetWindowRect(dskhwnd, winrect)
             Call ClipCursor(winrect)
         #End If
         'Stop and/or all other code goes here

NOTE: All code should follow this patch code in the subroutine.

STATUS
======

Microsoft has confirmed this to be an issue in the Microsoft products listed at
the beginning of this article. Microsoft is researching this problem and will
post new information here in the Microsoft Knowledge Base as it becomes
available.

MORE INFORMATION
================

To reproduce this behavior, add a DBGrid control to a form. In the click event
of the DBGrid control, stop the program by adding the stop keyword. When you run
the program and click the column headers of the DBGrid control, the mouse
pointer cannot be moved outside the borders of the DBGrid column headers.

Steps to Reproduce Behavior
---------------------------

1. Start Visual Basic or if it is already running, click New Project on the File
   menu.

2. Add a DBGrid control to the Form1 form.

3. Copy the following code sample to the Form1 code window.

         Private Sub DBGrid1_Click()
            Stop
         End Sub

4. On the Run menu, click start, or press the F5 key to start the program.

5. Click the column head of the DBGrid control. The cursor remains within the
   boundaries of the column headers.

Additional query words:

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Keywords          : kbVBp400 kbbuglist
Technology        : kbVBSearch kbAudDeveloper kbVB400Search kbVB400 kbVB16bitSearch
Version           : 4.0
Issue type        : kbbug

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Copyright Microsoft Corporation 2001.