The VisualCron Client is a separate application that constitutes the user interface for VisualCron. With the client you configure VisualCron and manage the Jobs and Tasks that are run by the server.
Several VisualCron clients can be connected to the same VisualCron server, typically a user both have the VisualCron client application and the VisualCron tray client connected to the same server. See main menu Server -> Client connections for a list of clients that are connected to the currently selected server. The VisualCron client application can also switch its server connection in the server selection drop down list in the leftmost part of the toolbar.