Bug 356804

Summary:	Breeze Task Switcher fails to visually highlight some windows' thumbnails while tabbing through
Product:	[Plasma] plasmashell	Reporter:	Daniel Boles <db0451>
Component:	general	Assignee:	David Edmundson <kde>
Status:	RESOLVED FIXED
Severity:	normal	CC:	bshah, nate, plasma-bugs-null
Priority:	NOR	Keywords:	regression, usability
Version First Reported In:	5.4.3
Target Milestone:	1.0
Platform:	Debian testing
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Daniel Boles 2015-12-16 23:24:49 UTC

I've got the Switcher set to Breeze them with the usual Alt-Tab as the main shortcut. When pressing this, the pane appears on the left with thumbnails of windows oriented vertically. One of these is highlighted by a box (in my case a light blue colour) as you tab through.

However, certain thumbnails do NOT get highlighted - the highlight box stays on the previous window. But, if I release Alt on the window I just (blindly) tabbed to, it then gets focussed as normal. Showing that it _is_ being 'selected' - but not properly visually highlighted to indicate this.

Also, when the selection has moved to a new thumbnail where the highlight erroneously isn't showing - if I keep Alt held and move my mouse cursor over the now (invisibly) selected thumbnail, the highlight box then moves to there where it should have been all along.

Please let me know if I can provide any relevant details to get this resolved.

Reproducible: Always

Steps to Reproduce:
1. Set Task Switcher to Breeze them and open a bunch of windows
2. Press Alt+Tab multiple times and notice that certain windows are not highlighted when they are selected by the Switcher
3. Releasing Alt gives the right window focus, showing that the window is being selected, just invisibly - though by moving your mouse cursor over the thumbnail, it gets highlighted properly as it should have been

Actual Results:
Certain windows are not highlighted (without manually moving the mouse cursor over them, clearly not useful behaviour)

Expected Results:
All windows should be highlighted when selected, as with any other task-switching widget

Happy to provide any relevant logs etc if required. Can probably record a video if absolutely necessary though I hope this is reproducible enough.

Comment 1 Daniel Boles 2015-12-16 23:29:35 UTC

Re what I said about the mouse cursor always updating the highlight - this is not _completely_ consistent as sometimes this doesn't work. It's kinda 50/50. sometimes the switcher not only won't highlight on hover - but won't even accept clicks to select certain thumbnails. These are usually - but seemingly not always - the same windows that get skipped by highlighting using the Alt+Tab.

These issues are probably related and hopefully simple to fix together. Thanks!

Comment 2 Daniel Boles 2015-12-16 23:35:58 UTC

As expected, if I tick on "Show selected window", it brings each window to the foreground in turn, not skipping any - though the highlight box in the sidebar still misses some, remaining desynchronised from the actual selection.

The alternative types of Switcher - Cover and Flip - also work as intended,

I find both of these much less aesthetically pleasing than a working Breeze switcher... though I think ideally I'd have the old centred KDE4 one back :P

Comment 3 Nate Graham 2017-11-28 21:52:49 UTC

Haven't ever seen this in Plasma 5.8+. Please leave a comment if you can reproduce this with more recent software.