Task Manager Settings: Force Row settings: on Maximum rows: 2 Grouping: Do Not Group Sorting: Manually I have 5 entries in the task bar, arranged as 1 3 5 2 4 When I start a 6th application the task bar entry appears in the space under the 5th one, as expected. When I start a 7th application, the task bar rearranges itself to be 1 3 5 4 6 7 2 Quitting the 6th application causes the taskbar to rearrange again, to 1 3 5 2 4 7 This makes the task bar almost unusable as the application I want to go back to could have been shifted to anywhere. Reproducible: Always Expected Results: I'd expect new applications to be placed in the first column that isn't full, with existing applications left exactly as they are. Quitting an application should shuffle all the ones after it downwards, leaving the ones before it untouched.
*** This bug has been marked as a duplicate of bug 215231 ***
The layout is row-major, not column-major. Column-major layout is being considered.
So what I'm seeing should be interpreted as 1 2 3 4 5 6 becoming 1 2 3 4 5 6 7 ? That makes a little more sense, but it's still horrible - entries in the task bar should never change position on screen unless they're moving to fill a space caused by an application before them having quit. Given that 215231 has been open since 2009 and is marked WONTFIX, which I find inexplicable as I can't imagine anyone finding this behaviour reasonable, I'll just use the 4.11.1 patch that's been posted to that bug rather than waiting for an upstream fix.
The bug situation is a little more complicated than that. The orginal 2009 bug report is about "Force rows" switching the layout behavior from row-major to column-major, which was "fixed" by making the behavior always row-major. None of which is particularly relevant now, since I rewrote the Task Manager from scratch for 4.11. In doing so I retained the row-major behavior that had been in place for several major releases by that point, because my initial goal given the complexity of the task and the time table was to achieve feature parity along with making, many, many bug fixes. You can read more about this here: http://blogs.kde.org/2013/07/29/kde-plasma-desktop-411s-new-task-manager The clock to add column-major sorting thus more appropriately starts now, not in 2009. I personally think that the people who want column-major sorting have a point and intend to add it back. Feel free to use that patch in the meantime, though it's not a production-ready solution I can ship.
Plasma 5.5 switched to column-major sorting.