DOCUMENT:Q192050  31-AUG-1998  [vbwin]
TITLE   :BUG: Resource Leak with 256 Color Bitmap/UseZOrder PaletteMode
PRODUCT :Microsoft Visual Basic for Windows
PROD/VER:WINDOWS:6.0
OPER/SYS:WINDOWS
KEYWORDS:

======================================================================
---------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Visual Basic Learning, Professional, and Enterprise Editions
   for Windows, version 6.0
---------------------------------------------------------------------

SYMPTOMS
========

You may see a loss of System and GDI resources when repeatedly loading a
picture if the Form's PaletteMode is set to UseZOrder and the Windows
system display color settings are set to 256 colors. Because of the
differences in the way that Windows 95/98 and Window NT manage memory, the
consequences of this problem may be more apparent on a computer running
Windows 95/98 than on a computer running Windows NT.

RESOLUTION
==========

Set the PaletteMode property of the form to a setting other than UseZOrder.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products
listed at the beginning of this article.

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

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

These steps require that you have a 256 color bitmap. If you have a bitmap
you would like to use, substitute it for "C:\test.bmp" in step 5. If not,
create a 2 x 2 inch bitmap using Paint or other software capable of
creating a bitmap.

1. On a machine running Windows 95/98, set the Windows display system color
   setting to 256 colors.

2. Start a new Standard EXE project in Visual Basic. Form1 is created by
   default.

3. Add a CommandButton and an Image control to Form1.

4. Set the PaletteMode property of Form1 to UseZOrder.

5. Add the following code to the module of Form1:

      Private Sub Command1_Click()
      Dim b As Boolean
      Dim i As Integer

      For i = 1 To 500
         Caption = Str(i)
         b = Not b
         If b Then
            Image1.Picture = LoadPicture("c:\test.bmp")
         Else
            Image1.Picture = LoadPicture("")
         End If
      Next i
      End Sub

6. From the File menu, choose Make Project1.exe.

7. Save the project and close Visual Basic.

8. Start the Windows Resource Meter, and display the Resource Meter window
   by right-clicking on the icon in the TaskBar, and selecting Details.

9. Run Project1.exe and click on the CommandButton. You should see the
   System and GDI resources decreasing. These resources are not reclaimed
   until you exit Project1.exe.

Additional query words: kbDSupport kbDSD kbVBp kbVBp600bug kbBitmap
======================================================================
Version           : WINDOWS:6.0
Platform          : WINDOWS
Issue type        : kbbug

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 1998.