The number of monitored connections showing at bottom of is the total of all connections currently being monitored.
It consists of all the Analysis Services, Availability Groups, Hyper-V, Replication, SQL Azure, SQL Server, VMware and Windows connections as seen in the left hand panel. It will exclude any connections that have been created but are now disabled.
As an example:
If user has a Windows server with 2 SQL Server instances on it, and user is monitoring the Windows server and both SQL Server instances, then this will count as 3 connections.