This probably also applies to Tumbleweed, but it is in Leap 15.2 that I am seeing the issue.
For a long time, I have configured KDE to disable touchpad if a mouse is plugged in. It is in the touchpad settings (part of “Input devices”).
Computer 1: I try to configure that setting. And the setting is nowhere to be found. However, it still works. KDE on this computer was originally configured in Leap 15.1, where the setting was available. So it works, but I cannot configure it.
Computer 2: Here, when I go to that configuration, I can still find it (and it works). On this computer KDE was originally configured for Leap 15.0 (or perhaps earlier), and the setting remains and is still configurable. However, if I create a new user on this computer, and configure KDE from scratch, then the configuration is not available. If I then copy “.config/touchpadrc” from the user that works, then it starts working for this new user, but still doesn’t show in the configurations.
Is this setting being deprecated? Or is this a bug that I should report to kde.org?
This configuration option is the main reason that I switched to using KDE a few years ago. I would really hate to lose the option.
The kcm (system settings) module for the touchpad now uses “libinput” rather than “synaptics”. It currently doesn’t support all of the functions previously available. It’s not the only setting that’s been “lost”.
I’m not yet troubled by this issue, as my only machine with a trackpad is on leap 15.1, and I won’t be updating that to 15.2 until around the midpoint of the 15.2 lifecycle. Over the first few days of initial trackpad use I made quite a few tweaks to the settings until I was comfortable using the pad… I hope I’m able to retain those.
In the (KDE) bug report you wrote
Here’s a strange thing. On one laptop, I see the old touchpad settings screen. That laptop was originally configured with openSUSE Leap 15.0, then upgraded. However, if I create a new user on that same computer, then I get the new touchpad settings screen with some settings no longer visible.
That, sort of, goes along with Nate Graham’s comment from the same bug report
… If you want to see that interface (and regain the missing features), then you’ll need to replace Libinput with Synaptics. …
What I don’t understand at the moment is what governs whether the Libinput or Synaptics driver is used… or, more specifically, how to specify which driver to use.
I also have Gnome installed. And it turns out that Gnome-Wayland uses libinput, while Gnome-X11 uses the synaptics driver. So I uninstalled the synaptics driver and locked it, to force Gnome-X11 to use libinput. The reason I can know that KDE was using libinput, was that the synaptics driver was not there at all.
What I’m finding a bit strange is, that in an Oracle VirtualBox VM, regardless of whether on a Desktop or, this Laptop (with an Elantech Touchpad (Synaptics)), the Leap 15.2 Beta KDE Plasma System Settings still show the Touchpad tabs in the same fashion as that for Leap 15.1.
I couldn’t try to change the settings because, my initial test VM didn’t pass the Laptop’s Touchpad through to the VM – I’m reinstalling with the ICH9 Chipset activated …
The Desktop is just that, a Desktop – it doesn’t have a Touchpad but, the KDE Plasma System Settings Touchpad tabs were still there and, despite the warning that, no Touchpad was found, the “Enable/Disable Touchpad” tab was selectable and indicated that the “Disable touchpad when a mouse is plugged in” was still there.
FWIW, this blog is one of several I’ve found that describes how to create a simple udev rule to automatically disable a touchpad when an external pointing device is connected (and another rule to re-enable the touchpad when not connected to an external pointing device). It might serve a s a workaround while KDE gets its act together around this.
I meant to comment about the beginning of that blog article.
As best I can tell, the issue is for people who have learned to touch-type. A touch-typist keeps the hands very close the keyboard, so is frequently bumping the touchpad. By contrast, a “hunt and peck” typist tends to keep hands well above the keyboard, and does not run into this problem.
That did not force using the synaptics driver. But then I notice that the power settings were also different between the two. There’s probably some setting for some input device that cause it to use the synaptics driver. But I don’t know what that is. I’m not about to try hunting down every related config file.