How to scroll unbound cxGrid with mousewheel when grid is unfocused

Hello, thank you for looking at this for me.
Here's my overall goal: Give the user a popup window from which they can select a City, State, Zip combination (records loaded from the DB into an unbound cxGrid).
The popup is displayed from a TcxButtonEdit containing a single "Down" button. The popup is displayed if the user clicks the "Down" button, of if they start typing within the text area of the TcxButtonEdit control.
It's important to note that the user must be able to enter a City, State, or Zip (depending on what's currently being selected) that does not exist in the grid.
When the popup is displayed due to the user typing, the popup does not receive focus. Instead, the TcxButtonEdit control retains focus (so that the user can continue to type text). Since the grid is unfocused, I use the following to perform incremental searching:
View.OptionsSelection.CellSelect := False;
View.Controller.IncSearchingText := text from TcxButtonEdit
View.OptionsBehavior.IncSearchItem := the grid column in the TcxGrid
If the user clicks the grid, I change the above to:
View.OptionsSelection.CellSelect := True;
View.Controller.IncSearchingText := '';
View.OptionsBehavior.IncSearchItem := nil;
When the grid has focus, there's no problem using the mouse wheel (obviously). However, I would like to be able to scroll the grid records programmatically when I detect WM_MOUSEWHEEL or CM_MOUSEWHEEL messages. I'm able to intercept these messages within the form that hosts the TcxButtonEdit control (TForm1 below). For example, using a TApplicationEvents component:
procedure TForm1.ApplicationEventsMessage(var AMsg: tagMSG; var AHandled: Boolean);
begin
  case AMsg.Message of
    WM_MOUSEWHEEL:
      if not View.Site.Focused then
        if FindVCLWindow(AMsg.Pt) = View.Site then
        begin
          View.Site.Perform(CM_MOUSEWHEEL, AMsg.WParam, AMsg.LParam);
          AHandled := True;
        end;
  end;
end;
This approach works fine for other controls on TForm1 (like a calendar) that are unfocused.
Above, I'm using View.Site because FindVCLWindow(AMsg.Pt) returns a TcxGridSite instance. I've tried sending CM_MOUSEWHEEL & WM_MOUSEWHEEL to the grid (Grid.Handle) as well with no luck.
Additionally, I've tried using SetCapture(Grid.Handle) and SetCapture(View.Site.Handle) before calling Perform(XX_MOUSEWHEEL, AMsg.WParam, AMsg.LParam);
You may ask me, "Why didn't you just use a TcxLookupComboBox?" I did, but I could not find a way to let the user enter text that was *not* in the ListSource.
Thank You in advance for your Help,
John