BUG: Option Button Value Changes When Group is Disabled (191720)


The information in this article applies to:

  • Microsoft Visual Basic Learning Edition for Windows 5.0
  • Microsoft Visual Basic Learning Edition for Windows 6.0
  • Microsoft Visual Basic Professional Edition for Windows 5.0
  • Microsoft Visual Basic Professional Edition for Windows 6.0
  • Microsoft Visual Basic Enterprise Edition for Windows 5.0
  • Microsoft Visual Basic Enterprise Edition for Windows 6.0
  • Microsoft Visual Basic Standard Edition, 32-bit, for Windows 4.0
  • Microsoft Visual Basic Professional Edition, 16-bit, for Windows 4.0
  • Microsoft Visual Basic Professional Edition, 32-bit, for Windows 4.0
  • Microsoft Visual Basic Enterprise Edition, 16-bit, for Windows 4.0
  • Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows 4.0
This article was previously published under Q191720

SYMPTOMS

You have a group of Option Buttons on a Visual Basic Form. When you disable them from code, the last one disabled will have its Value property changed to True, causing the Click event for that button to fire. This occurs only when all of the option buttons are disabled.

CAUSE

The problem occurs when the buttons are disabled while the current input focus is on one of the buttons. As each button is disabled in turn, the tab order advances the focus to the next available button in the option group. When the last button is disabled, its Value property is set to True, and its Click event is fired.

RESOLUTION

This behavior does not occur if the input focus is moved to another control before the buttons are disabled.

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

  1. Create a new Standard EXE project. Form1 is created by default.
  2. Add three Option Buttons to Form1.
  3. Paste the following code into Form1's code window: 
          Option Explicit

      Private Sub Form_Load()
          Option2.Value = True
      End Sub

      Private Sub Form_DblClick()
         Option1.Enabled = False
         Option2.Enabled = False
         Option3.Enabled = False
      End Sub

      Private Sub Option3_Click()
         MsgBox "Option3 Click"
      End Sub
  4. Run the project by pressing the F5 key. When the program starts, the input focus is set to Option2.
  5. Double-click somewhere on Form1. Note that the Click event for Option3 is fired when the button is disabled.
  6. To resolve the problem, add a Text Box to Form1. Then add the following line at the start of the Form_DblClick event: 
          Text1.SetFocus
  7. Re-run the program and double-click somewhere on Form1. This time the Click event of Option3 should not fire when the control is disabled.
Modification Type:MajorLast Reviewed:6/24/2004
Keywords:kbbug KB191720
©2004 Microsoft Corporation. All rights reserved.