Lag when clicking the Media Library tab

[nacin]

When clicking “Media Library”, it doesn’t actually switch over to the active tab until after the attachments query has run, which could take anywhere from a few moments to a few seconds. It should switch over immediately, then have a blank screen waiting for the attachments to come in. (Bonus: spinner.)

[koopersmith]

It actually isn't waiting for the attachments query to run, but if it has attachments, it renders them in one shot. The attachments view could definitely be optimized further — it is very much a v1 — but I am hesitant to introduce any changes there at this point.