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 a fresh installation of LXDE on Ubuntu 18.04, the tap gesture did not work for the touchpad of my Lenovo Y510P.

Installing Synaptics as  helped to solve the problem:

sudo apt install xserver-xorg-input-synaptics

Previously, xserver-xorg-input-libinput  was installed, and I did not manage to configure the tap gesture using this driver, properly.

I found this solution on

In Thunderbird 52.9.1 on Ubuntu 18.04, I found the oversized emojis annoying because they covered other messages in the inbox (e.g., in Facebook notification mails).

This issue seems to be unsolved currently (see here).

Fortunately, the situation can be mitigated by disabling the Noto Color Emoji font.

  1. Install the Font Manager tool: sudo apt install font-manager
  2. Open the Font Manager: font-manager
  3. Select System in the left panel and search for Noto Color Emoji in the right-hand side search box.
  4. Deselect the checkbox to the left of the font name.
  5. Restart Thunderbird. Now, the emojis should be replaced by placeholder glyphs containing digits.

Thanks to this thread for the solution, which I describe here in greater detail.

A behavior that annoyed me for some time was that Eclipse disabled autobuild (“Project -> Build Automatically”) on startup, no matter whether it was active during a previous, regular shutdown of the workspace.

I was unable to find a suitable setting in the workspace settings.

Finally, it turned out that the described behavior can be turned off (and on), by modifying an Eclipse Oomph configuration file as follows:

  1. Navigate to HOME/.eclipse/org.eclipse.oomph.setup/setups .
  2. Open the XML file user.setup .
  3. Navigate to a setupTask XML element with the key /instance/org.eclipse.core.resources/description.autobuilding , and set the value to true.

In my settings file, the corresponding XML fragment looks like this:




The Flat template is—in my opinion—a simple and elegant WordPress template.

Still, when printing blog pages, the output contains a large amount of whitespace.

CSS Customization

Using the template customization feature of WordPress, I adjusted the CSS of the Flat template to suit my needs.

The following CSS fragment is a suggestion for producing a more concise print rendering using the Flat WordPress theme.

@media print {
  .site-info, .entry-meta, .nav-links, .tags-links, a::after, #bit, .fa {
    display: none;
  #masthead .site-title, .hentry .entry-title {
    font-size: 30px;
    font-family: Handlee;
  #masthead .site-title {
    padding-bottom: 0px;
  .post {
    padding-top: 0px;
  .hentry .entry-content {
    padding-top: 0px;
  h2 {
    font-size: 24px;
    margin-top: 5px;
  table.easy-table {
    max-width: 90%;
  .easy-table th, .easy-table td {
    padding-top: 1px;
    padding-bottom: 1px;


I tested the print template live inside Firefox using the Developer Toolbar (Tools → Web Developer → Developer Toolbar) and the command media emulate print.

Chromium also offers a similar functionality in the Developer Tools (Ctrl+Shift+I) → Menu → More tools → Rendering → Emulate CSS media.

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>
  <keybind key="XF86AudioLowerVolume">
      <action name="Execute">
          <command>amixer -q sset Master 3%- unmute</command>

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>
  <keybind key="XF86AudioLowerVolume">
      <action name="Execute">
          <command>amixer -q -c 1 -- sset Master playback 3%- unmute</command>
  <keybind key="XF86AudioMute">
      <action name="Execute">
          <command>amixer -c 1 -- sset Master toggle</command>

By coincidence I recently found out how to open an Eclipse workspace via drag and drop on Windows.

It is actually a simple trick, but I want to share it anyway:

  1.  Create a link to the eclipse.exe that you want to use (e.g., named EclipseWorkspaceDragAndDrop on your Desktop).
  2. Open the properties of the link (e.g., via Alt+Enter).
  3. Locate the Target input field, whose content should end in eclipse.exe right now.
  4. At the very end of the input field, append -data.
  5. Open the Explorer (or suchlike), navigate to the parent directory of your workspace directory, and drag the workspace directory onto the link (e.g., EclipseWorkspaceDragAndDrop)
  6. Eclipse should startup into the selected workspace without asking you to choose one.


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.

PowerPoint is a great tool for creating figures. Recently, I created a number of relatively large figures that considerably exceeded the slide boundary.

However, if you scroll slightly across the borders of the figure (using the mouse wheel), PowerPoint switches to the previous or next slide, which is really annoying.

It seems taht this feature cannot be switched off in PowerPoint 2013, but, thankfully, I found the following pragmatic solution [1]:

  • Open the Master slide view
  • Place some forms (e.g., rectangles) very far outside the slide area in all four directions.
  • Close the Master slide view


[1] Microsoft Community: How to stop Powerpoint from jumping to next/previous slide when editing.

When using JUnit for creating unit tests, I have always felt annoyed that Eclipse keeps on suggesting (or even auto-importing) junit.framework.Assert, which is actually a deprecated type but appears first in the list of import suggestions.

To disable this behavior, one has to change the so-called Access Rules for the JUnit library.

To do this:

  1. Right-click you project and select Build Path -> Configure…
  2. Switch to Libraries tab and locate the used junit.jar
  3. Select Access rules and press Edit.
  4. Add a new rule with the rule pattern junit/framework/Assert and set its access level to Forbidden.
  5. Make sure that the rule appears before the junit/framework/* rule, which permits any acccess.

Now, Eclipse should only provide for one import quick fix, when using Assert. Even “Organize Imports” (Ctrl+Shift+O) should automatically find the correct solution now.

Thanks to this Stackoverflow post for hinting me at this solution.