In the marketplace search results, the thumbnails in the right column are partly blocked by DIVs from the rating number in the left column (div class="RatingNumber" (Chrome's 'Inspect Element' feature is SO awesome!) ). You have to click on the top or bottom quarter of the thumbnail to get around that div. The "DataArrowUp" and "DataArrowDown" DIVs also extend over the thumbnails, but don't actually interfere.
In Firefox, hitting enter in the Marketplace search box occasionally gives me "This XML file does not appear to have any style information associated with it. The document tree is shown below." followed by anywhere from 5 to a gazillion lines of XML. Doesn't seem to be related to search terms in any way I can discern. Using the Search button seems to work OK.