public void dispose() {
		// we can be disposed from outside the swing thread
		Swing.runLater(() -> {
			closeHover();
			hoverServices.clear();
		});

		program = null;
	}
Sets the object that decides where to place the popup window. 
@param popupWindowPlacer the placer
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/hover/AbstractHoverProvider.java