The expand icon disappears once you have more than 1500 queries stored across all query categories. In order to restore the expand feature (and the Find functionality), queries will need to be deleted until the number of saved queries is under 1500. For steps on how to delete queries, click Can I delete queries and reports?

The expand icon can also disappear from the Communications or Reports section of the database, due to the same limitation on the number of items that can be stored in either section. For example, if there are more than 1500 reports saved, on the Report Categories page the expand icon will no longer be available.