It's clear from the conversation in T7928 that this needs more discussion. Let's do it here:
Advantages of status quo (single-click to open)
- Makes opening files and folders much easier for users with poor dexterity or mousing skills, laptop trackpads, and touchscreens in particular (where double-clicking is practically impossible).
- More intuitive; many users on other platforms have never fully understood when they need to double-click, and end up cringe-inducingly double-clicking everything "just to be safe."
- More consistent with mobile, where double-clicking doesn't exist. Vastly more touch-friendly.
Disadvantages of status quo
- Unfamiliarity for users migrating from all other desktop platforms, which all select with single click and open with double-click. We discard up to 30+ years of muscle memory.
- Makes selection much more difficult by reducing the click target to a tiny square in the corner. For touch users, it's literally impossible, since the selection marker only appears on hover, and there is no hover with touch.
- Makes multi-selection in file open dialogs frustrating, since no selection marker appears and there is no visible method to select multiple files.
- Makes file save dialogs confusing. Single-clicking on a file suddenly no longer opens it. Why? Not clear. The UX breaks down.
Discussion
Let me mention that I actually really like the single-click setting. I just think it can't work without a lot of engineering effort put into resolving the above issues. Because right now, it's half-baked, halfhearted, and riddled with bugs. If someone proposed it in a patch today, we would block it on the above-mentioned objections, and possibly more.
If we're going to keep the feature used by default, then we need to make it work properly, and resolve the UX issues I detailed above. Mobile OSs that implement single-click-to-open (as well as GNOME apps) typically expose a dedicated "selection mode" that's invoked by pressing a "select" or "edit" button, and while in that mode, buttons for cut copy, paste, delete, and other contextually-appropriate actions become visible. If we're going to stay down this path, we need to be all in; the tiny little green selection button in the corner is not sufficient. We need to do serious usability and engineering work to accommodate common workflows in single-click mode vastly better than we do now.
If we aren't willing to do that or lack the resources, then we should consider it an experimental feature and not have it on by default, and not break people's muscle memory and experience for the sake of exposing them to a buggy, half-baked UX.
Summary of the discussion (including the arguments in from above to have a comprehensive list) - please update, so people don't have to read all comments.
Arguments brought up for single click
- Single click makes opening items easier, especially for users with poor dexterity or mousing skills or devices that it is hard to double click with (laptop trackpads, touchscreens) (1)
- Single click avoids confusion about what needs to be double clicked and what needs to be single clicked (leading to some users double clicking everything) (1)
- Single click is more consistent with mobile touch devices (1) - Argument against it is that mobile devices use a different input method (1)
- General articles advocating single click (1)
Arguments brougt up for double click
- People are often used to double click and might have muscle memory (1) - just because they are used to it, doesn't mean that double click is the best (1) - the way how others do things is not considered a valid argument (1) - reference to Jakob's law which says that how others do things should indeed be considered (1)
- Example list of people complaining (1) - One the other hand examples of Windows users wanting single click (1)
- Most other systems that use mouse input do rely on single click (including KDE distributions) - Kubuntu changed to double click (1) - an argument against that has been brought up that one should rather look at new users who never used a computer before (1) - comparison with keyboard layout decisions that mostly rely on users who already know the layout (1)
- When the goal is to get people to migrate, the behavior should be similar to the previous systems, users can then change the setting afterwards (1, 2)
- Selecting items is harder - one needs to use the small square in the corner (1, 2) - the need of selecting single items in the first place is questioned (1)
- Single click is currently not consistently implemented (1) - Things will probably not fixed in the near future, so change to double click until then (1)
- Qt file save dialogs don't open files on single click but select them (1)
- GTK file dialogs (like on Firefox) use double click (1) - applications can be told to use Qt dialogs () - that is currently not implemented, though () - that is wrong, it works at least with Firefox in openSUSE (seen on Tumbleweed, likely also on Leap) (1)
General
- Proposal of having the user choose this in a still to be implemented first start wizard (1)
- Concern of breaking the workflow for existing users (1) - Important point, but not an argument against a change, since this can be taken care of (1, 2)
- Idea to have it changed based on the input method used (1)
- Proposal to include telemetry in this decision (1) - telemety will not tell too much, since it is biased by defaults (1, 2)
- Link to the current approach to make use of telemetry (1)
