BUG: Scroll Control: UAE/GPF If Drag Method in GotFocus Event

 Last reviewed: June 21, 1995
Article ID: Q81955
The information in this article applies to:

- Standard and Professional Editions of Microsoft Visual Basic for 

  Windows, versions 2.0 and 3.0
- Microsoft Professional Toolkit for Microsoft Visual Basic programming 
  system for Windows, version 1.0

SYMPTOMS

An Unrecoverable Application Error (UAE) in Windows version 3.0 or a General Protection (GP) fault at address 0012:001E in Windows version 3.1 may occur when you perform a manual drag (using the Drag method) in the GotFocus event for an Instant Change Scroll Bar custom control (INSTSCRL.VBX in Visual Basic version 1.0) or the regular Scroll Bars control (in Visual Basic version 2.0 or 3.0) and change the focus to the Scroll Bar (or the Instant Change Scroll Bar custom control) in either the Change or the Changing event.

The Instant Change Scroll Bar custom control comes with the Microsoft Visual Basic Professional Toolkit version 1.0 for Windows. The capabilities of the Instant Change Scroll Bar were implemented in the regular Scroll Bars controls in both the Standard and Professional editions of Visual Basic versions 2.0 and 3.0.

STATUS

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

MORE INFORMATION

Steps to Reproduce Problem in Visual Basic Version 1.0

  1. Start Visual Basic or from the File menu, choose New Project (ALT, F, N) if Visual Basic is already running. Form1 is created by default.

  2. From the File menu, choose Add File. In the Files box, select the INSTSCRL.VBX custom control file. The Instant Change Scroll Bar tools appear in the toolbox.

  3. Place an InstHScroll or InstVScroll control and a command button on Form1.

  4. Double-click the Instant Change Scroll Bar control (or press F7) to open the Code window. Enter the following code in the Changing event: 

       Sub InstHScroll1_Changing ( )
      Command1.TabIndex = 0
      InstHScroll1.TabIndex = 1
   End Sub

   Add the following code in the GotFocus event:

   Sub InstHScroll1_GotFocus ( )
      InstHScroll1.Drag 1
   End Sub

  5. Press F5 to run the example. Click the scroll arrow of the Instant Change Scroll Bar and wait a few seconds. A UAE or GP fault will occur.

This problem occurs with both the InstVScroll and InstHScroll controls, and with the code above in either the Change or Changing events.

Additional reference words: buglist1.00 buglist2.00 buglist3.00 1.00 2.00
3.00
KBCategory: kbprg kbbuglist
KBSubcategory: PrgCtrlsStd

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Last reviewed: June 21, 1995
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