Unlike in the wired C-Bus world, sometimes units that were recently added to the wireless network, still may not appear after network scan. This usually happens if you already had units added to the wireless network via Learn process, but later had them disconnected from mains for a while and then again connected.
In such case Wireless Gateway may not be aware of new units on network as it is not polling the network constantly to check what was added or removed. To make it aware of the change and make C-Bus Toolkit correctly show the list of "Units on Network" do the following:
Press Update button on the "Units on Network" panel.
You will need to confirm the fact that you want to refresh cache on the Wireless Gateway. This confirmation is important because not only cache is going to be refreshed, but also this unit's Operational Statistics (you can see this on the Status page of the unit GUI). If you're monitoring Operational Statistics to determine for example the rate of collisions on the network, you may choose not to go ahead at this point.
Once the update is complete, you will see an information message.
As the message suggests you have to wait for some time before rescanning network while Wireless Gateway is polling the network. 50 seconds delay is necessary to complete the poll of about 30 units. if you have 5 units, waiting for 10 seconds may be enough.