I'm using Ubuntu 17.10 with GNOME shell and Numix-Circle icon theme.

When I hover over the Numix icon for Nightly Web Browser, which is pinned to the dock I get the title "Nightly Web Browser".

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But when I launch the program, another icon pops up at the bottom, with the name "Nightly".

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You need to add a proper StartupWMClass line to the .desktop launcher corresponding to the application (refer to this). Follow these steps:

  1. Open Files and go to your /usr/share/applications folder. Look for the "Nightly" file (i.e. the launcher for the application you want to fix) and copy it.
  2. Paste the file in ~/.local/share/applications. It should look like a file with the name <filename>.desktop.
  3. Right click on this .desktop file and open with Text Editor.
  4. Launch "Nightly" (i.e. the application you want to fix) from "Activities".
  5. Run xprop WM_CLASS in Terminal.
  6. Place the cursor over the opened "Nightly" window. The cursor should turn into a crosshair already. Click. You should get a WM_CLASS string for "Nightly" in Terminal.
  7. In the .desktop file opened in Text Editor and add the following line


    In place of OBTAINED-VALUE put a value you got from step 6 without any quotes.

  8. Save the .desktop file.
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    I am trying to do the same with PyCharm. Got "sun-awt-X11-XFramePeer", "jetbrains-pycharm-ce" as the output for step 6. I used StartupWMClass=jetbrains-pycharm-ce and it works. – d4nyll Jan 11 '18 at 15:59
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    9. Rename .desktop file to OBTAINED-VALUE.desktop (e.g. jetbrains-phpstorm.desktop instead phpstorm.desktop), works in Ubuntu 18.04 – Aleksey Deryagin Jul 12 '18 at 16:29
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    Thank you for the answer. It would be really nice to have an explanation of what happens. I don't want to blindly follow some instructions. What is going on and what does the fix do? Would be great if someone could help out. – marts Jan 26 '19 at 12:03
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    @marts Please go through this for an explanations: askubuntu.com/questions/367396/… – pomsky Jan 26 '19 at 12:05
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    @AlekseyDeryagin In step 6, I got WM_CLASS: not found. As the misbehaving application was kile and the name of the file org.kde.kile.desktop, I just added the line StartupWMClass=kile and it works. My wild guess is that the last full-stop separated part of the filename (right before .desktop) should match the StartupWMClass value. – Ansa211 Feb 11 '19 at 12:57

related to :

Kile icon buggy in left (launcher) bar (ubuntu 18.04)

On ubuntu 18.04

  • open the file : org.kde.kile.desktop
  • at : /usr/share/applications
  • add this line at the end of file : StartupWMClass=kile
  • press ALT+F2, r

It works for me

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