Edit control with transparent background scrolling issue

[ahal89]

I'm trying to make a EULA. So I have a multi line read-only edit control that the user needs to be able to scroll down on.

Additionally, since I'm using a custom skin for my main window background, the edit control background has to be transparent other wise it looks really ugly.

I simply used the WS_VSCROLL style to obtain the vertical scroll bar. The problem is that when I scroll down then up, the text doesn't refresh, i.e it draws on top of itself and creates garbage.

I've done some research, and I know that this is why:

case WM_CTLCOLORSTATIC: // Makes the static control backgrounds transparent
            ::SetBkMode((HDC)wParam, TRANSPARENT);
            return (LRESULT)::GetStockObject(NULL_BRUSH);   // Return NULL brush

What I don't know is how to fix it.
I've tried doing something like this:

case WM_SETTEXT:        // Ensures that text is not drawn on top of previous text
            if ( GetDlgCtrlID (hDlg) == EDIT_CONTROL_ID){ 
                ::InvalidateRect( hDlg, NULL, TRUE);
                DefWindowProc(hDlg, WM_SETTEXT, 0, lParam);
            }

This exact same code worked for a similar problem I had updating static text, but doesn't seem to work on the edit control (I'm guessing cause it doesn't fire a WM_SETTEXT on a scroll). I'm sure I have to intercept the EN_VSCROLL notification, but so far nothing I've tried has worked.

Any help is appreciated! (I'm also pretty new to win32 development)



EDIT: Ok, so I made some progress, but not much.. still need some help.

case WM_COMMAND:        // COMMAND MESSAGE
		    wmId    = LOWORD(wParam);
		    wmEvent = HIWORD(wParam);
		    // Parse the menu selections:
		    switch (wmId) {
			    case EDIT_ID:
			        if (wmEvent == EN_VSCROLL){
			            ::ShowWindow (GetDlgItem(hDlg, wmId), SW_HIDE);
			            ::SetDlgItemText (hDlg, wmId, g_eulaText);
			            ::ShowWindow (GetDlgItem(hDlg, wmId), SW_SHOW);
			            ::SetFocus(GetDlgItem(hDlg, wmId));
			        }
			        return TRUE;

then

case WM_SETTEXT:        // Ensures that text is not drawn on top of previous text
            if ( GetDlgCtrlID (hDlg) == EDIT_ID){     
                ::InvalidateRect( hDlg, NULL, TRUE);
                DefWindowProc(hDlg, WM_SETTEXT, 0, lParam);
            } 
            break;

This has two major problems.

1. It turns the background into non-transparent (even though it still acts as a transparent background... see 2)
2. When I click and drag the scroll bar, it still draws on top of itself

Actually, just found out that EN_VSCROLL doesn't get sent when the user clicks on the actual scroll bar, which means that capturing EN_VSCROLL might not work... sigh