If you want to perform some action on multiple objects at the same time, such as dropping (deleting) a number of tables, you can select all of them in the Databases tab list and then pick the action from the right-click menu:

To select multiple entries in the objects list, hold Ctrl and left-click on Windows/Linux or Cmd and left-click on Mac OS X.

You can also select multiple tree nodes for drag & drop operations, such as dragging a number of tables into the Query Builder.