What does window class mean?

Asked by Naja Melan on 2015-02-09

Hi,

the program has a setting called "Window Class". It's not very clear from the tooltip, nor from a google search what this really is.

I know I used to have a problem where gnome would consider different software as if it was the same, mixing up their icons and also sometimes focusing their windows instead of launching an instance of the second program, like different java programs who all had their exec property starting with "java ".

Would this setting help to alleviate such problem or is it something totally different?

Other than that great software, especially now since alacarte is broken in gnome3. It works on debian too.

Thanks

Question information

Language:
English Edit question
Status:
Answered
For:
Arronax Edit question
Assignee:
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Last query:
2015-02-09
Last reply:
2015-02-14
Florian Diesch (diesch) said : #1

Every window has a property called "window class" (or WM_CLASS). Often this is the same as or similar then the program name.
If you type

    xprop | grep WM_CLASS

in a Terminal and then click on a window it will print the window class (as far as I know there is no simple graphical way to do this).

This property is often used to guess the corresponding .desktop file for a window, and then use that .desktop file to get the icon, menu button, sidebar button, ... for that window.

Sometimes this doesn't work well - java programs are indeed often a problem. In that case it often helps to provide the window class in the .desktop file.

I've created a bug: https://bugs.launchpad.net/arronax/+bug/1422018 that the tooltip should be more helpful here. if you have an idea for a better tooltip feel free to comment there :-)

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