Open file dialog defaults to showing hidden files
Edit the file
~/.config/gtk-2.0/gtkfilechooser.ini
There is a line
ShowHidden=true
change to
ShowHidden=false
Save and close.
Worked for me!
You may have checked showing hidden files in preferences. In Nautilus (file browser) click Edit>Preferences and in Views tab if Show hidden files and backup files is ticked, remove the tick.
To fix this in 13.04, I had to right click on the dialog and uncheck "Show Hidden Files"