[chesnok]

Часть DialogProc:

case WM_DRAWITEM:
		{
			lpdis = (LPDRAWITEMSTRUCT) lParam; 
			DrawOwnControl(lpdis);			
			 
			break;
		}

void DrawOwnControl(LPDRAWITEMSTRUCT lpdis)
{
	HDC hMemDc = CreateCompatibleDC(lpdis->hDC);
	if(lpdis->CtlType == ODT_BUTTON) //its a button
	{
		LONG lStyle = GetWindowLong(lpdis->hwndItem, GWL_STYLE);
		if(lStyle & BS_GROUPBOX)
		{
			//groupbox
			LOGBRUSH lb;
			lb.lbColor = RGB(0, 0, 0);
			lb.lbStyle = BS_SOLID;
			lb.lbHatch = NULL;
			HBRUSH hBlack = CreateBrushIndirect(&lb);
			SelectObject(lpdis->hDC, hBlack);
			FloodFill(lpdis->hDC, 1, 1, RGB(125, 125, 125));
		}
		//button
		BOOL bDwnText;
		
		HBITMAP hBmpBtn = LoadBitmap(hInst, MAKEINTRESOURCE(IDB_RAISED_NOFOCUS)); //bitmap for button drawing, default = raised w/o focus
		bDwnText = FALSE;
		switch(lpdis->itemAction)
		{
		case ODA_SELECT:
			{
				if(lpdis->itemState & ODS_SELECTED)
				{
					//down
					if(lpdis->itemState & ODS_FOCUS)
					{
						//down focused
						hBmpBtn = LoadBitmap(hInst, MAKEINTRESOURCE(IDB_DOWN_FOCUS));
						bDwnText = TRUE;
					}else
					{
						//down non-focused
						hBmpBtn = LoadBitmap(hInst, MAKEINTRESOURCE(IDB_DOWN_NOFOCUS));
						bDwnText = TRUE;
					}
				}
				break;
			}
		case ODA_DRAWENTIRE:
			{
				if(lpdis->itemState & ODS_DISABLED)
				{
					//grayed
					//the only difference is gray text instead of white
				}
				break;
			}
		case ODA_FOCUS:
			{
				//raised with focus
				if(lpdis->itemState & ODS_FOCUS)
				{
					hBmpBtn = LoadBitmap(hInst, MAKEINTRESOURCE(IDB_RAISED_FOCUS));
					bDwnText = FALSE;
				}
				break;
			}
		}
		SelectObject(hMemDc, hBmpBtn);
		StretchBlt(lpdis->hDC, lpdis->rcItem.left, lpdis->rcItem.top, lpdis->rcItem.right - lpdis->rcItem.left, lpdis->rcItem.bottom - lpdis->rcItem.top, hMemDc, 0, 0, 91, 26, SRCCOPY);
		uCurTextLen = GetWindowText(lpdis->hwndItem, szCurText, MAX_PATH);
		SetBkColor(lpdis->hDC, RGB(76, 88, 68));
		SetTextColor(lpdis->hDC, RGB(255, 255, 255));			
		RECT rcForText = lpdis->rcItem;
		rcForText.left += STEAM_TEXT_OFFSET;
		if(bDwnText)
		{
			//down text
			rcForText.left += 2;
			rcForText.top += 2;
		}
		//draw text
		DrawText(lpdis->hDC, szCurText, uCurTextLen, &rcForText, DT_SINGLELINE | DT_VCENTER);

		DeleteDC(hMemDc);
	}else
		if(lpdis->CtlType == ODT_LISTBOX) //listbox
		{
		    //to be done yet
		}
	return;
}

То, что выделено красным - попытка обработать group box, не увенчавшаяся успехом