Feature request - synchronized xyz value

Feature request: Multiple values when examining a pixel in synchronized mode.

Often when examining image differences I have to focus on specific pixels. It would be useful if this could be done on the fly - when examining synchronized windows, in addition to showing the XYZ, also show multiple values, one for each image.

Start by locating the synchronized-window mode and the existing pixel-examination display that shows XYZ values. Trace how synchronized images are selected and how the current value is presented. Done means examining a pixel in synchronized mode shows a separate value for each image, alongside the existing XYZ information.

Written by the indexing model from the issue text.