In 15.04 you can add the "power manager plugin" to the panel. It displays your mouse's battery status in the menu (or at least it should). If it doesn't you can check whether it's the fault of the underlaying technology, which is UPower (the power manager only reads the device info it gets from UPower and then displays it). Simply run "upower -d" in the terminal and check whether your mouse shows up.
The reason I'm mentioning this as a potential culprit is because UPower underwent a rather big upgrade/transition with 15.04. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-power-manager in Ubuntu. https://bugs.launchpad.net/bugs/1448834 Title: mouse battery not shown after upgrade Status in gnome-power-manager package in Ubuntu: New Status in xfce4-power-manager package in Ubuntu: New Bug description: In Xubuntu 14.04 and 14.10 the power manager dropdown menu showed the battery level in my wireless logitech mouse. However after upgrading to 15.04 the mouse battery status is not shown. ProblemType: Bug DistroRelease: Ubuntu 15.04 Package: xfce4-power-manager 1.4.3-0ubuntu1 ProcVersionSignature: Ubuntu 3.19.0-15.15-generic 3.19.3 Uname: Linux 3.19.0-15-generic x86_64 ApportVersion: 2.17.2-0ubuntu1 Architecture: amd64 CurrentDesktop: XFCE Date: Sun Apr 26 19:49:19 2015 ProcEnviron: LANGUAGE=en_US PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: xfce4-power-manager UpgradeStatus: Upgraded to vivid on 2015-04-23 (3 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/1448834/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp