FIX: Setting Windowless Control to Transparent Prevents Animation (257645)

MORE INFORMATION

Steps to Reproduce Behavior

1. Create a new ActiveX Control project in Visual Basic. UserControl1 is created by default.
2. Change the Height and Width property of UserControl1 to 1680.
3. Change the Windowless property of UserControl1 to True.
4. Add the following code to UserControl1:

   Option Explicit
   
   Private x As Long
   Private y As Long
   
   Public Property Get BackStyle() As Integer
       BackStyle = UserControl.BackStyle
   End Property
   
   Public Property Let BackStyle(ByVal New_BackStyle As Integer)
       UserControl.BackStyle() = New_BackStyle
       PropertyChanged "BackStyle"
   End Property
   
   Public Property Get BackColor() As OLE_COLOR
       BackColor = UserControl.BackColor
   End Property
   
   Public Property Let BackColor(ByVal New_BackColor As OLE_COLOR)
       UserControl.BackColor() = New_BackColor
       PropertyChanged "BackColor"
   End Property
   
   Private Sub UserControl_Initialize()
       x = Width
       y = x
   End Sub
   
   Private Sub UserControl_Paint()
       If Ambient.UserMode = False Then Exit Sub
       Randomize
       Dim i As Integer
       Dim j As Integer
       For j = 1 To 40
           For i = 1 To 30000
               If i Mod 10000 = 0 Then
                   Circle (x * Rnd, y * Rnd), 50
               End If
           Next
       Next
   End Sub
   
   ' Load property values from storage
   Private Sub UserControl_ReadProperties(PropBag As PropertyBag)
   
       UserControl.BackStyle = PropBag.ReadProperty("BackStyle", 1)
       UserControl.BackColor = PropBag.ReadProperty("BackColor", &H8000000F)
   End Sub
   
   ' Write property values to storage
   Private Sub UserControl_WriteProperties(PropBag As PropertyBag)
   
       Call PropBag.WriteProperty("BackStyle", UserControl.BackStyle, 1)
       Call PropBag.WriteProperty("BackColor", UserControl.BackColor, &H8000000F)
   End Sub
   					

5. From the File menu, select Add Project. Choose Standard EXE and click Open. Form1 is created by default.
6. Close the (designer) window for UserControl1.
7. Add two instances of UserControl1 to Form1. They are named UserControl11 and UserControl12.
8. Change the BackColor property of both UserControls to something other than grey.
9. In the Project Explorer, change the startup project by right-clicking on Project2. Select Set as Startup.
10. Press the F5 key to run the project. Note that you can see circles being drawn on the controls (animation.)
11. Stop the project and change the BackStyle property of UserControl12 to 0 (Transparent.)
12. Press F5 to run, and note that you do not see the circle animation on UserControl11. The form becomes transparent while animating, but you only see the circles on the control after the animation has taken place.