Multi-thread for opening new folders

[Dave Ahlswede <mightyquinn charter net>]

At the moment in Nautilus, when you open a new folder, the rest of the
app is put on hold until it's finished displaying. With small folders,
this isn't a problem, but if you happen to open one with several hundred
files, there's a significant delay, where you can't do anything
file-manager related, you have non-repainting windows, etc.

I suspect this wasn't nearly as much of a problem before spatial mode
was introduced, but it's very inconvenient. Would it be feasible for
Nautilus to start a separate thread for the opening of a new folder, so
that the application doesn't seem to grind to a halt?