From Forum Nokia Wiki

I used CEikEdwin::SetBackgroundColorL() to draw a custom Background color in 2nd and it works fine, but not draw in 3rd. For 3rd edition, you should use CParaFormat and TextView.

CustomEdwin.cpp

void CMyEditorContainer::ConstructL(const TRect& aRect)
{
   ...
   iEdwin = new (ELeave) CEikGlobalTextEditor;
   iEdwin->SetContainerWindowL(*this);
   iEdwin->SetBackgroundColorL(KMyCustomColor);
   iEdwin->TextView()->SetBackgroundColor(KMyCustomColor);
   ...
}
 
Everytime after you change the text:
  CParaFormat* pf = new (ELeave) CParaFormat();
  CleanupStack::PushL(pf);
  pf->iFillColor = KMyCustomColor;
  TParaFormatMask mask;
  mask.SetAttrib(EAttFillColor);
  iEdwin->ApplyParaFormatL(pf, mask);
  CleanupStack::PopAndDestroy();

CustomEdwin.h

class CMyEditorContainer: public CCoeControl, MCoeControlObserver
{
   ...
    private:
        CEikGlobalTextEditor*   iEdwin;
   ...
}

Links

How to use custom background color for edwin in 2nd

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