Author: Peter Below

I need to create an invisible window over a webbrowser component so that I can stop 
mouse clicks.

Answer:

There are much better ways to block mouse clicks to a specific window. You can use 
a handler for the Application.OnMessage event, for example:

1   procedure TMainform.FormCreate(Sender: TObject);
2   begin
3     Application.OnMessage := AppOnMessage;
4   end;
5   
6   procedure TMainform.AppOnMessage(var Msg: TMsg; var Handled: Boolean);
7   begin
8     case Msg.message of
9       WM_MOUSEFIRST..WM_MOUSELAST, WM_MOUSEWHEEL:
10        if Msg.hwnd = Webbrowser1.HWND then
11          Handled := True;
12    end;
13  end;