If you go into the options you can click on your actual open channels and that will show your incoming/outgoing.

Think of it like an abacus, at the moment all the beads are on your side, but if you send some over to the other side, now they have some "liquidity" which can be sent back over to your side. The abacus (channel) will only ever have the same number of beads, but if your beads are all over your side you won't be able to receive, and if they are all at the other end you have none to send.