Bug 635610 made the loading indicator for the Disco pane show earlier. However, for some people, the indicator flashes before disappearing again (because the page had loaded). The loading indicator for the details view has a strategy to cope with this: it's delayed by 100ms and then fades in over 1000ms. However, the norm for database access is almost-instant, but the same isn't true for network access.

There is a completely new discovery pane and this bug is no longer relevant.