(svn r1679) Fix: dropdown menus now returns the index of the string that was clicked even if a previous item is hidden

This bug was not triggered by the current code, but it's easier to code new features if you do not have to think about such limitations 
like you can't hide an item in the middle of the list ;)

vehicle_gui.c

@@ -867,7 +867,6 @@ static void ReplaceVehicleWndProc(Window *w, WindowEvent *e)
 		} break;
 
 		case WE_DROPDOWN_SELECT: { /* we have selected a dropdown item in the list */
-			//potiential bug: railtypes needs to be activated 0, 1, 2... If one is skipped, it messes up
 			WP(w,replaceveh_d).railtype = e->dropdown.index;
 			SetWindowDirty(w);
 		} break;