In version 3.1 the switch name was moved to a separate column.
It may first appear as the rightmost column, but you can move it anywhere within the view, as shown below. And if it isn't displayed for you for some reason, please check View - Columns - Switch in the main menu.
If you mean that device names are blank after you discover new switches, please make sure you have ticked one or more columns in SNMP Device Discovery window. The ticked columns will be used to form device names.
We added this selection functionality to provide flexibility and let users choose how they want to name their devices.