You know what's better? Hammer. Sorry, but this looks useless. I can't even see a purpose to using this in conjunction with Hammer. Once again, sorry, but I voted no. I can see that it's an interesting concept, but as a user it seems impractical and clunky.
I heard from a friend who has a pirated copy of portal 2, and it looks like that hes not the only one who cant update to dlc2. but i never heard of someone who buyed portal 2 and doesnt have the dlc2 update, so please buy the game. (Maybe im Wrong, but i dont think so)
I've used this before PTI with my friend, and it's actually quite cool, but it's temporary, and can only be used for simple maps.
I'm not sure I believe that, but have you tried verifying your cache while connected to the internet?
If you delete the game and redownload it through steam, it will download the most recent build of the game; which will include dlc2.
One thing that I DID like about po2edit was that starting in the mock void allowed more creative freedom than the PTI starting room. That sounds odd, but what I mean is that you feel a little less limited in the structure of the map. The PTI starting room makes it a little harder to get the idea juices flowing. I don't know, maybe (probably) it's just me that feels that way.
It shouldn't be used for map making, but it's quite fun just moving around and changing things.
I find this usefull to test physics in portal 2 BEFORE making the maps.