SUMMARY *** It seems Task Manager uses the theme's icons for windows. In various cases, in particular when grouping is not selected, using actual windows' icons is more beneficial and makes the task manager more useful. *** STEPS TO REPRODUCE 1. Currently the icons used by the task manager come from the selected theme 2. For applications with multiple windows this means that even if those windows have different icons which may also indicate the window's functionality these are displayed with the 'parent' application icon (taken from the theme See the screenshots for a couple of good examples: - QjackCtl [1] is an application which can create multiple windows each of which has different functionalities and therefore icons. The task manager in this case shows all the same windows. - In the second screenshot Rosegarden [2] opens different kinds of editing windows: notice each has a slightly different icon to indicate the kind of editor. This is not reflected by the task manager which is using the applications 'stock' theme icon. It would be good to have the functionality (and option) to use the actual window icon displayed in the task manager. This might be related to https://bugs.kde.org/show_bug.cgi?id=384357 but is more general and focuses on the Virtualbox icon, not on the underlying functionality.
Created attachment 154762 [details] multiple windows application icons not shown in task manager
Created attachment 154763 [details] multiple windows application icons not shown in task manager
Add: another case is applications with the same name. For instance "Element" is a well-know Matrix client but also a (maybe less well known) music sequencer / patchbay. In the screenshot below you can see that Element (the sequencer) is incorrectly given the other Element icon.
Created attachment 154764 [details] Applications with same name but different (and different icon) are assigned same icon
Cannot reproduce in qjackctl, all windows have the same icon in the titlebar. The second bug should be reported to Breeze.
Hi Fushan Wen, Thanks for checking into this! Actually the fact that all icons are the same (and taken from the theme, in this case Breeze) is exactly the bug... Icons should all be different as foreseen by the app developer because windows are underlining different functionality / behaviour By contrast the 'Present Window' plugin (triggered e.g. by screen edges) correctly show the App's "native" icons. See screenshot below.
Created attachment 154795 [details] Example of present windows correctly showing app's native icons
Unfortunately sometimes window icons are worse, not better, which is a major reason why historically we've used themed icons. Another is so that the icons that appear in the Task manager match the icons for the app that appear elsewhere. If we didn't do that, they wouldn't match anymore, and confuse people. That said, the icons already don't match up with the icons used in the Alt+Tab Task Switchers, so we already confuse people. And your points are valid. Perhaps we should rethink this for the non-icons-only task manager.
Thanks for your insight Nate. Please also do not forget multi-window applications which use different icons for different (functional) environments like the examples provided (I'm sure there's more in the Linux application ecosystem). As there's probably a degree of personal preference in these cases, IMHO the ideal would be to allow users to chose with some sane defaults. I will say that using theme icons as a default works in most cases, the cited examples being exceptions. Lorenzo
This looks like the same issue as bug 476794. I'm going to merge this into that report, since the other has more up to date information. Thanks! *** This bug has been marked as a duplicate of bug 476794 ***