Swing Menus and Toolbars - The Definitive Guide to Java Swing - page 174

JPopupMenu Properties
The 16 properties of JPopupMenu are listed in Table 6-9. Many more properties are also inherited
through JComponent , Container , and Component .

Table 6-9. JPopupMenu Properties
Property Name Data Type Access

accessibleContext AccessibleContext Read-only

borderPainted boolean Read-write

component Component Read-only

invoker Component Read-only

label String Read-write bound

lightWeightPopupEnabled boolean Read-write

margin Insets

Read-only

menuKeyListeners MenuKeyListener[ ] Read-only

popupMenuListeners PopupMenuListener[ ] Read-only

popupSize Dimension

Write-only

selected Component Write-only

selectionModel SingleSelectionModel Read-write

subElements MenuElement[ ] Read-only

UI PopupMenuUI Read-write bound

UIClassID String Read-only

visible boolean Read-write

The most interesting property of JPopupMenu is lightWeightPopupEnabled . Normally, the
JPopupMenu tries to avoid creating new heavyweight components for displaying its menu items.
Instead, the pop-up menu uses a JPanel when the JPopupMenu can be displayed completely
within the outermost window boundaries. Otherwise, if the menu items don't fit, the JPopupMenu
uses a JWindow . If, however, you're mixing lightweight and heavyweight components on different
window layers, displaying the pop-up within a JPanel might not work, because a heavyweight
component displayed in the layer of the menu will appear in front of the JPanel . To correct this
behavior, the pop-up menu can use a Panel for displaying the menu choices. By default, the
JPopupMenu never uses a Panel .