A supermenu (a JS9 Menubar whose id starts with SUPERMENU_, and with a data-displays attribute) can control multiple JS9 displays simultaneously, so you can change colormaps, scales, etc. on all displays. Or you can click on an individual display to make it the selected display for the supermenu. (Click that display again to unselect). You can also select a display from a supermenu's File menu, which contains a list of selectable displays. Thus, a supermenu can control several displays collectively or each one individually.

In this demo, we have loaded Chandra (red), Galex (green), and Spitzer (blue) images of colliding galaxies NGC 2207 and IC 2163 into a single display:

• With a single display, the supermenu behaves like a normal menu
• Choose "File:separate:separate these images" to make three separate displays
• Use the Scale menu to change the scale of all three images to "histeq" and back to "log"
• Choose "WCS:wcs reproject:chandra.fits" to reproject the Spiter and Galex images using the Chandra WCS (reproject does not act on itself).
• Change the contrast/bias individually on any of the images (i.e., mouse manipulation is still tied to the individual images)
• You also can move the two Spitzer and Galex displays around in the page (i.e., they are lightweight windows)
• Click the chandra.fits (red) image to select it as the supermenu's target image (notice it gets a green highlighted border)
• Choose "File:separate:gather all images here" to move the Spitzer and Galex images back to the original display
• Choose "View: Blending", turn on Image Blending to view the blended images as one
• Again choose "File:separate:separate these images" to make three displays, so you can adjust contrast/bias individually
• Choose "File:separate:gather all images here" to move the Spitzer and Galex images back and display the blended images (since blending is still turned on)

JS9 Demos:

• the basics
• setting the size of the JS9 display
• menubar styles
• web page control
• preloading images into JS9

• multiple instances of JS9
• control multiple displays with one menu
• creating a JS9 instance dynamically
• syncing images in multiple displays

• adding plugins to JS9
• the imexam plugin
• pan and zoom
• overlaying catalogs
• dynamic selection of displays

• image blending
• RGB composite images
• creating new colormaps

• remote data analysis
• running tasks when a region changes

• displaying different FITS datatypes
• support for large FITS files

• using the all-in-one files
• PNG representation files vs FITS files