A Boolean member variable that indicates the location of the pop-up menu.
When the user presses the menu button, the application shows a pop-up menu. The framework will display the pop-up menu either under the button or to the right of the button. The button also has a small arrow that indicates where the pop-up menu will appear. If m_bRightArrow is TRUE, the framework displays the pop-up menu to the right of the button. Otherwise, it displays the pop-up menu under the button.