clr!SafeReleasePreemp() crash while deleting C# object from C++ application

Question

i have a C# Managed.dll and it is loading in C++ App using CWnd::CreateControl(). In C++ app its creation and destruction is done as follows

void MyDlg::Initialize()
{
	m_pManagedCtrl = new ManagedCtrl();// C# control
	m_pManagedCtrl->Create("Sample.ManagedControl", dwStyle, Rect, this, 111111);
}

void  MyDlg::UnInitialize()
{
	m_pManagedCtrl->DestroyWindow();
	delete m_pManagedCtrl;
	m_pManagedCtrl = NULL;
}

Is it the correct way. Some time i am getting crashes in clr!SafeReleasePreemp() while closing MyDlg. 

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Thanks, Renjith V R