From our manual, 5.3 Bluetooth Connection When the icon of a client device remains in the [Paired Devices]-list, there will be no Bluetooth connection between the Across Server computer and the client device. If you want to temporarily disable the Across operation for a device, therefore, leave its icon in the [Paired Devices]-list. When Across Client works on a client device, Bluetooth will be automatically connected (or disconnected) between the Across Server computer and the client device located in the [Client Devices Layout] when Bluetooth signal of both devices is available (or unavailable). When Across Client does not work on a client device, Across Server will try to connect to the client device when you click the [Connect]-item from the context menu popped by right-click on the client device icon.
