Its a switch - it can either pass thru one or the other input. There are two control signals to it - that are hooked up to rfswitch1 and rfswitch2. The only valid configurations are when rfswitch1 is off and rfswitch2 is on, or the other way round.
configs in which rfswitch1 and rfswitch2 are both either on or off are "invalid" configs - they don't hurt anything, but none of the rf ports will reach the rtlsdr. So you won't see any signal at all in such configs.
There is no way to have both ports reach the rtlsdr at the same time - at least not in the software. But as I said, the invalid config, by itself, isn't going to cause any permanent damage to the Dreamcatcher.