DB Cruiser -- Explore Tables -- Schemas & Catalogs:
 
(see below for explanation)
 
Explanation:
 
The first thing in using Explore Tables is usual select a schema and a catalog (if any). The meanning of database schema and catalog is varialty among database products.

You may use Database Schemas and Database Schemas buttons on the Main Menu to find out the actual meanings of them in a particular database product.

For example, in Oracle, a schema corresponds to a user, but in Sybase, it corresponds to an onwer. The drop-down list on the following screen lists all the schemas (users) in a particular Oracle database.

The default value for both schema and catalog is "ALL" (see the default screen), that means list tables from all schemas and all catalogs in the database, as long as you have the permission to view them.