Top N Dimensions not available for new events

[jordibruin]

When I'm adding new events with custom parameters I am unable to select them from the Top N Dimensions list until real life data has been received (I think).

It would be nice to be able to just paste a value in like is possible for the filter (although the problem also exists there, I first have to select another filter before I can manually edit it)

I run into this problem for every event I make, and it takes a lot of extra steps just to add one as a result.