It took me a while to find out how to change the file explorer application that Firefox uses when I press the “Open Containing Folder” button in the download manager.

I first tried adjusting the MIME type mappings in /usr/share/applications/defaults.list, /usr/share/applications/mimeinfo.cache, and ~/.local/share/applications/mimeapps.list, as suggested here and here. No success.

Finally, by grepping my home directory for “dolphin” (which I wanted to get rid of as default browser), I found another default mapping in ~/.config/lxsession-default-apps/settings.conf

In this file, I needed to adjust the line starting with file_manager/installed  as follows (one line!):

file_manager/installed=File Manager PCManFM,pcmanfm,system-file-manager,/usr/share/applications/pcmanfm.desktop,;

After installing Lubuntu 16.10 on my Lenovo Y510P, the key binding for volume control (Fn + Left/Right) were not working.

I found out that all key bindings can be easily configured using the XML configuration file ~/.config/openbox/lubuntu-rc.xml.

The default commands were configured as follows:

  <!-- Keybinding for Volume management -->
  <keybind key="XF86AudioRaiseVolume">
      <action name="Execute">
          <command>amixer -q sset Master 3%+ unmute</command>
      </action>
  </keybind>
  <keybind key="XF86AudioLowerVolume">
      <action name="Execute">
          <command>amixer -q sset Master 3%- unmute</command>
      </action>
  </keybind>

When executing these commands on the console (lxterminal), I received the following error message:

$ amixer -q sset Master 3%+ unmute
amixer: Unable to find simple control 'Master',0

It appeared that the simple channel name was wrong.

The problem could easily be fixed by manually selecting the first sound card via -c 1 (the option -q serves to suppress any standard output):

amixer -q -c 1 -- sset Master playback 3%+ unmute # increase volume by 3%
amixer -q -c 1 -- sset Master playback 3%- unmute # decrease volume by 3%

The modified part of the configuration files looks as follows. Note: The X server needs to be restarted for the changes to take effect!

 <!-- Keybinding for Volume management -->
  <keybind key="XF86AudioRaiseVolume">
      <action name="Execute">
          <!--<command>amixer -q sset Master 3%+ unmute</command>-->
          <command>amixer -q -c 1 -- sset Master playback 3%+ unmute</command>
      </action>
  </keybind>
  <keybind key="XF86AudioLowerVolume">
      <action name="Execute">
          <command>amixer -q -c 1 -- sset Master playback 3%- unmute</command>
      </action>
  </keybind>
  <keybind key="XF86AudioMute">
      <action name="Execute">
          <command>amixer -c 1 -- sset Master toggle</command>
      </action>
  </keybind>

After installing Dropbox on a fresh Lubuntu 16.10, I was missing the Dropbox icon in my task bar.

From several posts, I learnt that installing the package libappindicator1 as follows should help:

sudo apt-get install libappindicator1

Alas,  the icon was still missing.

Finally, I found the a post that suggested to set the environment variable XDG_CURRENT_DESKTOP to Unity:

dropbox stop && env XDG_CURRENT_DESKTOP=Unity dropbox start

After verifying that this worked, I modified the corresponding desktop entry that corresponds to Dropbox (For a full list, see Start menu -> Preferences -> Default applications for LXSession). The entry is located in ~/.config/autostart on my system. I copied the file Dropbox.desktop to Dropbox-custom.desktop and set the Exec line to the following content.

Name=Dropbox-custom # If you like - helps to distinguish this file from the one generated by Dropbox
# ...
# Was before: Exec=dropbox start -i
Exec=env XDG_CURRENT_DESKTOP=Unity dropbox start -i

Afterwards, I disabled the option Start Dropbox on system startup in the Dropbox preferences – otherwise, Dropbox would override the .desktop entry.

Credit: Thanks for idobrinescu, who proposed this fix for Elementary OS Freya.