Bug present in all versions of LXR (since the beginning)!
When diff'ing, hyperlinks (included files, identifiers) for file in the left pane are faulty because they use the current values of 'variables', which is adequate for file in the right pane. This environment should be saved and set to the @dargs value-set before marking up the first file. After markup, the current environment must be restored.
Minor bug since 1.0.0: in the sub-title "diff markup between ... and ...", the value-sets are exchanged showing the value of variables for the other file.