@Override
		public void stateChanged(ChangeEvent e) {
			Object source = e.getSource();
			if (!(source instanceof ButtonModel)) {
				return;
			}

			ButtonModel buttonModel = (ButtonModel) source;
			if (buttonModel.isArmed()) {
				// item entered
				DockingWindowManager.setMouseOverAction(delegateAction);
			}
			else {
				// item exited
				DockingWindowManager.setMouseOverAction(null);
			}
		}
Show a popup containing all the actions below the button

@return the popup menu that was shown
Ghidra/Framework/Docking/src/main/java/docking/menu/MultipleActionDockingToolbarButton.java