@Override
			public void actionPerformed(ActionContext context) {
				if (instructionsFromAction.isSelected()) {
					refProvider.showInstructionsFrom();
					referencesToAction.setSelected(false);
					instructionsFromAction.setSelected(true);
					dataFromAction.setSelected(false);
				}
				// don't let the user de-click the button, since these buttons change in
				// response to each other, like a javax.swing.ButtonGroup set
				else {
					reselectAction(instructionsFromAction);
				}
			}
Tells a plugin that it is no longer needed.
The plugin should remove itself from anything that
it is registered to and release any resources.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/symtable/SymbolTablePlugin.java