Hi Ioannis!
The Summary Report plug-in is loading another version fo JQuery, which doesn't seem to play well with our jquery.js and colorbox.js. I *think* the sequence is:
1. we load JQuery
2. we load Colobox and get ready to use it
3. Summary Report Plug-in loads JQuery, disabling colorbox
It raised another issue, which is loading the same JavaScript file several times. We learned how to fix it during that major rewrite of uno-choice, by using adjuncts: https://github.com/jenkinsci/image-gallery-plugin/commit/d7da1caa0e1d9e0acf259baeec15a1747a696db8#diff-504a7d9bca452d02b12d9a69b4a4f0f4R2
This issue is not responsiblefor JENKINS-22888, but is fixed anyway. A simple solution would be the Summary Report Plug-in to use adjuncts as well.
The adjuncts are defined in Stapler, the Web framework used by Jenkins (created by Kohsuke). Jenkins/Stapler is able to load an adjunct only once and control it across several plug-ins.
So I believe that if the Summary Report Plug-in started using it as well, this issue would disappear.
Upon closer inspection this issue is only present when the image gallery adds to a build page that already contains another report. I have noticed this with build pages that contain both an XML Summary Display publisher report and an image gallery report, but i'm not sure if this is repeatable with other type of reports on the build page.