WinForms tabpage not repainting on form resize

Question

Is there a reason why a .NET WinForms TabPage doesn't fully repaint its background when I resize the Form? It should be completely white (in Windows 7), but a portion remains gray (SystemColors.Control, most likely). Whenever I hit the maximize button, currently visible TabPage background doesn't get redrawn. Also, if I resize it, I need to move the form past the screen boundaries in order for it to get painted.

The same thing happens if I minimize and then restore the form. In that case the TabPage background remains grey. Child controls are rendered properly (labels, for example, keep their white backgrounds).

I am using Windows 7 32-bit, .NET 3.5. Tab control was added using the Visual Studio designer, and contains a couple of labels and two text boxes. I haven't changed any native style flags related to paint messages.

[Edit]

I have created a test project, source is uploaded here.

This is how the window looks initially:

This is how the window looks after I minimize it and then restore it:

Note the change in TabPage background color.

Answer 1

I fixed this by adding a call to tabControl.Refresh() inside the tabControl's ClientSizeChanged method. Note that that's for the overall Tab Control and not each individual Tab Page.