In the Task Manager Settings dialog, I have "Grouping" set to "By Program Name". When the "Only when the task manager is full" box is unchecked, grouping works as expected. However, when this box is unchecked, windows are never grouped. The attached screenshot shows my taskbar when several dozen windows from the same application are opened; I certainly consider the taskbar to be "full" but the windows are not grouped. I can reproduce this problem with several different applications (showimage, kmail, etc.) so I assume grouping is broken in general. Reproducible: Always Steps to Reproduce: 1. In the Task Manager Settings, set "Grouping" to "By Program Name", and check the "Only when the task manager is full" box. Then Apply the settings. 2. Open a large number of windows in the same application. Actual Results: 3. The entries in the task manager are not grouped. Expected Results: 3. The entries in the task manager should be grouped.
Created attachment 100584 [details] Screenshot showing bug
Sorry, there's a typo in the original report. Instead of "However, when this box is unchecked", I meant to write "However, when this box is checked".
The Task Manager backend was fully rewritten for Plasma 5.7, and bugs like this should be fixed now.