BUG: Mouse Captured After Clicking DBGrid Column Header

• Standard, Professional, and Enterprise Editions of Microsoft Visual Basic, 16-bit and 32-bit, for Windows, version 4.0

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
   
   

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