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!):

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:

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

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):

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

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:

Alas,  the icon was still missing.

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

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.

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.