Override CSplitterWnd (m_cxBorder & m_cyBorder Problem)

Hello CP users,
I want to override CSplitterWnd
Here is what I did:

class CMySplitter : public CSplitterWnd
{
public:
	CMySplitter()
	{
		m_cxSplitter = m_cySplitter = 4;
		m_cxBorderShare = m_cyBorderShare = 0;
		m_cxSplitterGap = m_cySplitterGap = 4;
		m_cxBorder = m_cyBorder = 2;
	}
};

I have did many testing manipulating these member variables, & I found that:
m_cxSplitter should be >= (m_cxBorder * 2)
&
m_cySplitter should be >= (m_cyBorder * 2)
Or-else the application will crash when the user try to resize the splitter window.
I am really confused why is this !
And the main frame border rectangle of the splitter window will not be painted correctly (Invalidated) if the m_cxBorder > 2 or m_cyBorder > 2

Can any body help me to make this last repaint correctly when the user try to resize the splitter window.

Thank you for your understanding.

Tags: C++, Visual C++ 6.0, MFC