this bug has been forwarded from https://launchpad.net/distros/ubuntu/+source/gedit/+bug/62132

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1) I need to open another source file, so I Open...

2) gedit nicely displays the contents of the last directory I've open anything from, which often contains several dozen source files.

3) But only on very rare occasions am I interested in a ".py~" file, and I've never felt the need to open a ".pyc" file, so I select "All Text Files" instead of "All Files" so I can more quickly find the ".py" file I'm looking for.

4) 53 seconds later, I feel the need to open some other ".py" file, but to my constant annoyance, gedit has reverted to "All Files", so I must select "All Text Files" again.

5) Repeat.

....
At the very least the All Files / Text Files state should persist during a given session, but please don't bother doing it this way if you do anything at all: save it permanently with gconf key. Persistence of state always makes an application easier to learn and quicker to use.
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Fixing this bug may also alleviate the symptoms of bug 329291