Hi Dave,
Regarding your second comment,
Almost all the libraries that I have checked uses Jquery UI which is quite heavy.
Please share your comments about using these libraries.
Meanwhile currently I have implemented zoom in/out functionality in graphical explain.
I have added two buttons on left top corner of panel (see the attached screen shot),
which you can use to zoom in/out the graph.
Please do review it and let me know your comments about them.