protected void fireFocusListeners(FocusEvent ev) {
		switch (ev.getID()) {
			case FocusEvent.FOCUS_GAINED:
				for (FocusListener listener : focusListeners) {
					listener.focusGained(ev);
				}
				break;
			case FocusEvent.FOCUS_LOST:
				for (FocusListener listener : focusListeners) {
					listener.focusLost(ev);
				}
				break;
			default:
				throw new IllegalArgumentException("" + ev);
		}
	}
Fire the given event on all registered focus listeners

@param ev the event
Ghidra/Framework/Docking/src/main/java/docking/widgets/textfield/TextFieldLinker.java