Today I was re-arranging my imported models using the Furniture Library Editor 1.1, when I noticed some unexpected behaviour (on my Ubuntu PC).

Accidentally I found that when modifying the data, by turning the preview picture of the model, the incorrect picture (I mentioned this in an earlier post ) is replaced with the new, correct picture. Closing the edit window, the new, correct picture is shown in the list as well. Great!

This is an undocumented behavior of the editor (I still have in mind to write a small tutorial for the Furniture Library Editor). And here is an other one: you can enlarge or reduce the picture with the mouse wheel. [;)]

When checking the imported files, I found that none of them were present. All the old files are still there (even though I changed the extensions from *.sh3f to *.old), but none of the new 54 Mb file. Am I doing something wrong?

I don't think so. [:(]
You should avoid to update the hidden .eteks directory files yourself (or go there only to delete unwanted files since there's no tool to uninstall SH3F, SH3T, SH3P or SH3L files yet). As Sweet Home 3D file extensions association doesn't work under Linux, install a new SH3F or SH3T file with Furniture > Import furniture library or Furniture > Import textures library menu items.
As there's no menu item to install SH3P and SH3L files, you can install these files with the command line:
- launch a Terminal window,
- drag and drop SweetHome3D icon in the Terminal window to copy its path,
- drag and drop the icon of the SH3x file in the Terminal window,
- finally press Enter in the Terminal window to launch Sweet Home 3D with the given file as parameter.
I'm sure you can do it even if you're not a programmer! [;)]