A minor bug: using the HTML version of the Gallery, folder names with " ' " character, are not supported.
For instance I had a gallery with folder name "Coup d'etat". Clicking on that folder, X2 didn't show the thumbnails related to the images loaded into that folder.
Last, it sometimes happens that not always the thumbnails are loaded. Refreshing the page, the thumbnails are eventually loaded.
It seems to be a random problem (I currently use Safari 4 beta on Ma OSX).