Today I’ve bumped into some weird problem with PHP files comparison using Eclipse PDT and Subclipse (SVN).
When a file was selected and “Compare with… Latest from Repository” option was chosen, the comparison window become gray, no code source was displayed and no error message was shown. It was just the same if you tried to compare a file with your local history or two separate files with each other.
It turned out to be a Subclipse bug which can be easily fixed by adding following update-site to Eclipse:
and installing the displayed packages.
Full bug description is available here.