One can use the left most mouse button to click on any image, in any column, and the other two images will be updated with the appropriate position.
NOTE: In the JIV window, you can "right-click" to get popup menus. One useful aspect is to turn on the 'sync all cursors' option so that all three column are updated with each left mouse click.
When looking at the images, remember that left is left and right is right!
On some platforms, the images are not displayed properly at startup. Simply click in the grey or black images to update the screen. (For example, clicking on a sagittal image will update the coronal and transverse iamges.)
For information on the JIV, the Java Image Viewer, please read: