PRB: Duplicate Control Boxes in MDIForm When Using Status Bar (201502)

MORE INFORMATION

Steps to Reproduce Behavior

1. Create a Visual Basic Standard EXE project. Form1 is created by default.
2. From the Project menu, choose Add MDI Formand then click the Open button to add a multiple document interface (MDI) Form to the project.
3. From the Project menu, choose Components, and select "Microsoft Windows Common controls X.X" from the components list and then click OK.
4. Change Form1's MDIChild property to True.
5. Add a StatusBar control to both Form1 and to MDIForm1.
6. Double click "MDIForm1" from the project window to make it the current form.
7. From the Tools menu, choose Menu Editor. Create a menu item specifying "Open" in the Caption text box and "mnuOpen" in the Name text box. Click OK.
8. From the Project menu, choose Project1 Properties and change the Startup Object to MDIForm1.
9. Add the following code to the General Declarations section of MDIForm1:

         Option Explicit
   
         Private Sub mnuOpen_Click()
            Dim frm As Form
            Set frm = New Form1
            frm.Display Me
         End Sub
   
         Public Property Let ShowStatusbar(bShowStatusbar As Boolean)
            On Error Resume Next
            If bShowStatusbar = True Then
               Me.StatusBar1.Visible = True
            Else
               Me.StatusBar1.Visible = False
            End If
         End Property
   					

10. Add the following code to the General Declarations section of Form1:

          Option Explicit
    
          Private m_ParentForm As MDIForm
    
          Public Sub Display(ParentForm As MDIForm)
             Set m_ParentForm = ParentForm
             Me.Show
          End Sub
    
          Private Sub Form_Resize()
             If m_ParentForm Is Nothing Then
                Exit Sub
             End If
             If Me.WindowState = 2 Then
                m_ParentForm.ShowStatusbar = False
             Else
                m_ParentForm.ShowStatusbar = True
             End If
          End Sub
    					

11. Run the application. Click the "Open" menu item. Maximize the child form. Click the "Open" menu item again and you will notice the duplicated control boxes at the upper right side.

Steps to Work Around the Behavior

1. Replace the code in the General Declarations section of MDIForm1 with the following:

         Option Explicit
   
         Private Sub mnuOpen_Click()
            Dim frm As Form
            Set frm = New Form1
            frm.Display Me
         End Sub
   
         Public Property Let ShowStatusbar(bShowStatusbar As Boolean)
            On Error Resume Next
            Dim i As Integer
            Dim bOneMaximized As Boolean
   
            If bShowStatusbar = True Then
               If Forms.Count > 0 Then
                  For i = 0 To Forms.Count - 1
                     If Forms(i).WindowState = 2 Then
                        bOneMaximized = True
                        Exit For
                     End If
                  Next i
               End If
            End If
   
            ' Only set it to be true when there is no maximized child form.
            If bShowStatusbar = True And bOneMaximized = False Then
               Me.StatusBar1.Visible = True
            Else
               Me.StatusBar1.Visible = False
            End If
         End Property
   					

2. Run the application and repeat step 11. The application will now behave properly.