Once I click Properties, I get a dialog with a lot of items on the left. The bottom one is for Extended Properties, with a simple add/edit/delete grid. Here I can see the property(ies) I’ve added.
However this is cumbersome for me. I’d much rather find a way to query the information, which is what I need to do with an application of some sort. I’d think sp_help would work, but it doesn’t.
Extended properties, like Service Broker, was a great idea that floundered because there was never a good UI. Given how much fighting Steve has to do to see one object’s properties, it’s no wonder they’re so relatively unused. And that’s a shame, because with the right tooling, they can be a great way of documenting data structures.