The rules for dragging and dropping the three types of App Builder objects are explained below. An error message will be displayed if you attempt to drop an object on an illegal target.
Panes (control pane, text pane, draw area pane, term pane) can be dropped on a main window, a custom dialog, or on another pane. See "Creating and Editing Pane Entities" for more information.
As noted above, a menu bar is on the Controls palette, but it is not really a control. It can only be dropped on a main window. A menu bar can be dropped anywhere on a main window; it will always appear at the top of the window.