I have a 2560x1440 Dell U2711 screen connected by Displayport to laptop running Ubuntu intel driver (15.10 standard Kubuntu packages). Sometimes, but not every time, when the laptop resumes and the external screen is connected, only a small section of the external screen is active. Luckily, I can open Display Configuration using the launcher of Alt+F2, move Display Configuration into the sliver of screen using Right Click > More Actions > Move and readjust the screen layouts then hit Apply which fixes the issue in all instances. See attached photos of screen. Only the part of the screen showing the background is active. I don't know if this is related to Kscreen. Reproducible: Always Steps to Reproduce: 1. Resume laptop with external DP connected screen 2. See result in attachments to be uploaded 3. Actual Results: Sliver of screen shows and is active Expected Results: Both the laptop screen and external screen should be active and arranged in the last used display layout for that screen setup I'm setting this as Major as it makes KDE unusable. I doubt a new user would find a way out of this without Turning It Off And On Again.
Created attachment 95151 [details] Photo showing section of screen showing upon resume The cursor position is the furthest it will travel to the right.
Created attachment 95152 [details] Photo showing section of screen with Disp Config open and layout shown After rearranging the screens and hitting apply, both screens come back.
Have a feeling this was fixed in 5.5 as it doesn't happen anymore on Kubuntu 15.10 with Plasma 5.5 from backports.