Design decision: Remove hover from Kickoff's category sidebar
Background
Kickoff has a sidebar showing app categories. Hovering the pointer over one of them switches the main view to show that category's apps.
The issue
What happens if the cursor passes over a category on its way to click on something? The visible category could get changed such that you can't see the thing you wanted to click on anymore, and that's super annoying.
In the past we had a delay in switching, but that annoyed people too by making the system feel slow. So we replaced it with a triangle mouse filter, which makes the category only switch for mostly-vertical movement, not diagonal movement. This helped a lot, and was more widely accepted by users.
However we still do get complaints, because the filter is not perfect: it still switches categories undesirably if you don't move your pointer in a straight line towards the target, and categories don't get switched immediately on hover if you move the pointer in too diagonal a direction. It feels janky:
In addition, switching categories is somewhat slow, and allowing hover to rapidly switch categories triggers a fairly bad bug: https://bugs.kde.org/show_bug.cgi?id=483205.
Finally, switching on hover is inconsistent and violates the HIG, as no other sidebars in KDE software behaves this way. Menus behave this way, but Kickoff is not a menu.
We have already added a user-facing option to move the sidebar to the other side of the popup, which fixes some of these issues by not requiring the pointer to pass over the category list to reach the main view. However this amounts to asking users to fix our design mistakes. I think adding that option was a mistake; if we want the sidebar to be on the right, we should just make it always be there for its inherent benefits (main view closer to the pointer's starting position).
Desired outcome
Click to switch categories and remove the "switch on hover" effect. It's buggy, it violates the HIG, and its remaining usability issues are fundamentally unfixable.
This will change the UI of a core part of Plasma and require some re-learning from users. I believe the benefits are worth it and the learning process will not be painful, because Kickoff will be becoming more consistent with other KDE software, not less.
Facilitator
Julius Enriquez (@linuxpusher)
The discussion is beginning on 3 October 2024.
Decision
The hover feature will be kept but made off by default. By default, switching categories will require a click.