private void savePopupTarget(MouseEvent event) {
		nextPopupTarget = null;
		V vertex = popupSource.getVertex(event);
		if (vertex != null) {
			nextPopupTarget = vertex;
		}
		else {
			E edge = popupSource.getEdge(event);
			nextPopupTarget = edge;
		}

		if (nextPopupTarget == null) {
			// We've moved off of a target. We will clear that last target so the user can
			// mouse off of a vertex and back on in order to trigger a new popup
			lastShownPopupTarget = null;
		}
	}
Sets the enablement of this class's popup
@param visible true to have popups enabled
Ghidra/Framework/Graph/src/main/java/ghidra/graph/viewer/popup/PopupRegulator.java