The Monitor tab has a check box to enable the display of incoming searches. When checked Limewire is liable to display a message:

Your client is a leaf node shielded by an Ultrapeer.

OK, so Limewire acts as either a leaf node or an Ultrapeer.

In the Connections tab Limewire's mode of operation is described as either:

[client] or [ultrapeer]

So what happened to our leaf node ?