@Override
	public void requestFocus() {
		if (lastFocusedComponent != null && lastFocusedComponent.isShowing()) {
			lastFocusedComponent.requestFocus();
			return;
		}

		if (placeholder == null) {
			return;	// this implies we have been disposed
		}
		placeholder.getProvider().requestFocus();
	}
Notifies the header that an action was removed.
@param action the action that was removed.
Ghidra/Framework/Docking/src/main/java/docking/DockableComponent.java