I'm a bit old school and like to move about my desktops by moving the mouse to the edge of the screen and having it 'flip' to the next desktop in that direction. FVWM users will know what I'm talking about.

The problem I'm running into is that the mouse doesn't always immediately move to the opposite edge of the screen and I end up flipping twice. It doesn't always happen, but it does maybe 1/3rd to 1/2 of the time. Hopefully this will explain it better:

Move mouse to left edge of desktop
The desktop flips to the next desktop to the left
Cursor doesn't relocate to the right edge of the desktop, but stays on the left
Desktop flips again, to the next desktop to the left

I have my desktops in a 3x3 grid and the desktop flipping wraps around. It happens with all edges, not just the left. Speed of movement does not seem to be a factor; I've slowly moved the mouse up to the edge, and it stayed there on the next desktop.

A cursory search on the KDE bugtracker has failed to find any bugs related to this.

My setup:

Kubuntu 15.04 with kwin version (according to dpkg-query) 4:5.2.2a-0ubuntu1, upgraded from 14.10 (I think - 14.something anyway) with KDE 4.x
Twin monitor setup running Twinview on NVidia proprietary drivers
AMD64 architecture

I'm a bit of a KDE noob (I used KDE a bit before I switched to GNOME 0.20, don't remember exactly when that was, but it was in the 90s) so I'm asking here so that I can try anything obvious before I post a bug on the tracker.

I can't reproduce the issue of the non (immediately) warping cursor (which is the root of all evil here), but you can mitigate the outcome by increasing the cooldown time.
Run "kcmshell5 kwinscreenedges" and increase the reactivation delay (notably the gap to the activation delay)

About the cursor: does it never warp or just "too late"?

I adjusted it up to half a second, but no dice. Same as before, just takes a bit longer.

You're right about it being a problem with the cursor not warping. When it doesn't warp, it never warps. If I'm real careful, I can make it switch desktops only once, and it'll sit against the (wrong) edge indefinitely.

Is it a rodent or a touchpad? (Or maybe even a digitizer?)

Rodent. Gear Head LM6500BLK. I've had it for a while, and it had no problem under KDE 4.x.

It's got one of those DPI switch buttons on it, and I get the behaviour at all three settings.

I did dig out my Wacom tablet (which hasn't been attached) and tried it out, but of course the mouse doesn't warp with it - it's not supposed to.

You could try to edit ~/.config/kwinrc and in the [Windows] section add

Code: Select all

ElectricBorderPushbackPixels=0


*WARNING* the electric borders will fire immediately after the next kwin restart:

Code: Select all

kwin_x11 --replace &


If that "fixes" it, the pushback collides with the intended warpin - if not, either the warp fails completely or something else™ manipulates the mouse position at that moment (where because of the random behavior, I'd assume the latter case)

Gave that a shot. On an (I assume) unrelated note, kwin sure does spam the console, doesn't it?

Anyway, it doesn't appear to have worked. What happens now is the desktops immediately jump when moved to the edge, which makes sense. The problem is that it moves a random number of desktops. Usually just one (the desired behavior), but sometimes two or three.

I've reverted the change (it's really unusable with that setting).

I'm going to add a new user to the machine and see if that user has the problem. If so, it's a problem with my installation - if not, it's a problem with my settings. None of my desktop settings from KDE 4 carried over, so I assumed it was clean, but now I'm beginning to have second thoughts on that.

Well, the other user account I created didn't have the problem, so it's definitely something with my configuration, not a problem with the install.

Assuming that I didn't just get lucky with the other account and it didn't happen because it happens randomly and I'm down the bell curve somewhere.

Anyway, I'm going to nuke the config later today. If anyone has any other ideas, I'd love to try them - I'd rather fix the current config than start with a new one.

Hey, did you ever find a solution to your problem? Deleting my KDE config doesn't seem to help.