PubMed Search Box Redesign
No, you are not imagining it. NLM has indeed made changes to the search box in PubMed and the two related databases, MeSH and NLM Catalog. An X replaces the Clear button. Links are moved from above to below the search box. Advanced Search is now just Advanced. Also, the Advanced Search Box now allows one to scroll through all of the entries instead of only seeing the first few terms.
For more details, see the NLM Technical Bulletin article: PubMed, MeSH and NLM Catalog Search Boxes Modified. Happy searching everyone!