Here's my 5 cents. ( tl;dr - use gnome and gdm )
I've been running Ubuntu 16.04.2 for long time on Dell Latitude E7250 without any problems using Gnome. I have two DELL external monitors, one connected with HDMI straight to laptop and the other connected with DisplayPort to the docking station. HDMI connected monitor is pivoted. Last week my laptop came for IT suppport after reinstallation of Ubuntu due to some other reasons. Now the desktop manager was Unity. When locking screen and automatic screen off, my system froze completely. I changed back to Gnome. Still same effect. Then I changed also from lightdm to gdm. -> setup is the same as before the reinstallation -> no problems any more with screen locking. -- You received this bug notification because you are a member of DX Packages, which is subscribed to compiz-plugins-main in Ubuntu. Matching subscriptions: dx-packages https://bugs.launchpad.net/bugs/1295267 Title: Windows change Monitor/Desktop after screen lock Status in Unity: Fix Released Status in Unity 7.1 series: Fix Released Status in compiz-plugins-main package in Ubuntu: Fix Released Status in unity package in Ubuntu: Triaged Bug description: I run a dual monitor configuration, with one portrait and one landscape. I nearly always have multiple applications open in multiple windows across both monitors and all virtual desktops. When I lock the screen and then unlock, my application windows will move from their original position. Sometimes they are in completely random positions; Other times they seem to get the monitors confused, and rather than being in the top half of the portrait monitor they are on the top half of the landscape monitor; Sometimes it is only a new desktop, but the monitor position is the same; Sometimes it is the same desktop, but on the other monitor. Description: Ubuntu 13.10 Release: 13.10 What I expect to happen: When I unlock my computer, all the windows are in the same position on the same monitor and desktop as I left them. What actually happens: When I unlock my computer, some or all of the windows have been changed to a random position on a random monitor and/or desktop. To manage notifications about this bug go to: https://bugs.launchpad.net/unity/+bug/1295267/+subscriptions -- Mailing list: https://launchpad.net/~dx-packages Post to : dx-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~dx-packages More help : https://help.launchpad.net/ListHelp
