public void keyPressed(KeyEvent e) {
			// react to pressing escape
			if(e.getKeyCode() == java.awt.event.KeyEvent.VK_ESCAPE) {
				if(nodeToDrag != null) { // stop dragging a node, and undo
					nodeToDrag.getPosition().assign(nodeToDragInitialPosition);
					nodeToDragDrawCoordCube = null;
					nodeToDrag = null;
					parent.redrawGUI(); // node position has changed, full repaint 
				}
				if(nodeToAddEdge != null) {
					nodeToAddEdge = null;
					targetNodeToAddEdge = null;
					repaint(); // no need to redraw whole gui, just repaint layer
				}
				if(zoomRect != null) {
					zoomRect = null;
					repaint();
				}
			}
		}