gedit needs to avoid freezing the ui when working on files on slow storage

[Kwinz]

Binary package hint: gedit

How to reproduce:
1. Use gedit 2.30.3 from Ubuntu 10.04.
2. Open one or more files from slow storage (e.g. sshfs over 100kbit/s connection).
3. When working, opening and storing the UI will often become unresponsive.
This will result in delayed response to clicks, scrolling and sometimes even gray out the whole window.
It is not only constrained to the current file but will affect all open tabs.

 I think gedit needs some more multi-threading, doing the blocking tasks in the background not annoying the user.

[David Tomaschik (matir)]

Reported to upstream.