Не знаю, есть ли вообще пакеты для lubuntu 13.10? На sourceforge я нашёл только исходники. Если умеете компилировать...
Скачал тарбол, прочитал - оказалось корректирующий релиз: Changes on 1.2.2 since 1.2.1:
* Fixed display name of created shortcut after dropping from another application.
* Fixed the screen for context in fm_launch_command_simple().
* Added KDE archiver "Ark" into archivers list.
* Fixed parsing order of directories in XDG_DATA_DIRS and XDG_CONFIG_DIRS.
* Added a possibility for application that was started (by PCManFM or any other application that uses LibFM) to never die after our application (i.e. its parent) was closed.
* Fixed possible memory leak in fm_config_load_from_file().
* Corrected g_content_type_guess() call with file sample. This may help with correct file type detection.
* When calculate total file sizes in directory, filesize of directory now is skipped.
* Fixed problem with memory consumption in case image has big dimension but not so big filesize - in that case loading may consume all the available memory to create bitmap. The file dimensions should also be checked against thumbnail_max configuration variable.
* Fixed problem with starting custom command from application selection dialog. This stopped to work with new GLib versions.