Update: MFC-Steuerelemente in überlappenden IFRAMEs empfangen unnötige WM_PAINT-Meldungen

// Code in the header file:
	virtual BOOL OnSetObjectRects(LPCRECT lpRectPos, LPCRECT lpRectClip);

// Code in the implementation file:
#include <afxpriv2.h>
#include <..\src\afximpl.h>
#include <..\src\ctlimpl.h>

void MyGetClippingCoordinates(LPCRECT pPosRect, LPCRECT pClipRect,
	LPRECT pIntersectRect, LPPOINT pOffsetPoint)
{
	int clipLeft = 0;
	int clipTop = 0;

	if ((pClipRect == NULL) || IsRectEmpty(pClipRect))
	{
		CopyRect(pIntersectRect, pPosRect);
	}
	else
	{
		IntersectRect(pIntersectRect, pPosRect, pClipRect);
		clipLeft = pClipRect->left;
		clipTop = pClipRect->top;
	}

	pOffsetPoint->x = min(0, pPosRect->left - clipLeft);
	pOffsetPoint->y = min(0, pPosRect->top - clipTop);
}

BOOL CTmpCtrl::OnSetObjectRects(LPCRECT lprcPosRect, LPCRECT lprcClipRect)
{
//	return COleControl::OnSetObjectRects(lprcPosRect, lprcClipRect);
	ASSERT(lprcPosRect != NULL);

	// Remember the position rectangle.
	m_rcPos = *lprcPosRect;

	// Calculate complete rectangle, include the tracker if it is present.
	CRect rectPos = m_rcPos;
	if (m_bUIActive && m_pRectTracker != NULL)
	{
		// Save new clipping rectangle (for DestroyTracker).
		if (lprcClipRect != NULL)
			m_pRectTracker->m_rectClip = *lprcClipRect;

		// Adjust tracker rectangle to new dimensions.
		CRect rectTmp = rectPos;
		rectTmp.OffsetRect(-rectTmp.left, -rectTmp.top);
		m_pRectTracker->m_rect = rectTmp;

		// Adjust the "true" rectangle to include handles/hatching.
		UINT nHandleSize = m_pRectTracker->m_nHandleSize - 1;
		rectPos.InflateRect(nHandleSize, nHandleSize);
	}

	// Now clip the rectangle as appropriate.
	CRect rectClip;
	MyGetClippingCoordinates(rectPos, lprcClipRect, rectClip, &m_ptOffset);

	// Move the outer window first, and then move the inner window.

	if (!m_bInPlaceSiteWndless)
	{
		CWnd* pWndOuter = GetOuterWindow();
		
		//BEGIN CHANGE.
		if (pWndOuter != NULL)
		{
			static CRect oldClipRect(0, 0, 0, 0);
			if (oldClipRect != rectClip)
				::MoveWindow(pWndOuter->m_hWnd,
					rectClip.left, rectClip.top,
					rectClip.Width(), rectClip.Height(),
					TRUE);
			oldClipRect = rectClip;
		}
		//END CHANGE.
		if (pWndOuter != this)
			MoveWindow(m_ptOffset.x, m_ptOffset.y,
				rectPos.Width(), rectPos.Height());
	}

	return TRUE;
}