SUMMARY If the “Press left and right buttons for middle-click” option is enabled, a very noticeable amount of latency gets added to mouse clicks. I can't say exactly how much it is, but fiddling around with reaction speed tests gives me a difference of somewhere around 40-60ms. If this is not fixable, there should at least be a warning, since this can have a big impact, especially for games. STEPS TO REPRODUCE 1. Enable “Press left and right buttons for middle-click” option. OBSERVED RESULT Latency added to mouse clicks. EXPECTED RESULT No change in latency.
I think the delay is inevitable -- we need to wait a bit to see if we are getting clicks from both buttons and emit a middle click. With that said, a warning that this increases latency would be nice.
Definitely a good junior job, yeah!
A possibly relevant merge request was started @ https://invent.kde.org/plasma/plasma-desktop/-/merge_requests/2129
Git commit b155f77b207f00c85e8344e6832ca8852001cf2c by Nate Graham, on behalf of Wladimir Leuschner. Committed on 21/03/2024 at 18:36. Pushed by ngraham into branch 'master'. kcms/{mouse,touchpad} Mention that middle button emulation increases latency Add a ContextualHelpButton to the middle mouse click emulation option that informs the user that activating this option increases the click latency. FIXED-IN: 6.1 M +25 -17 kcms/mouse/kcm/libinput/main.qml M +25 -19 kcms/mouse/kcm/libinput/main_deviceless.qml M +30 -23 kcms/touchpad/kcm/libinput/touchpad.qml https://invent.kde.org/plasma/plasma-desktop/-/commit/b155f77b207f00c85e8344e6832ca8852001cf2c