I am still having this issue. Just built two machines with a fresh Ubuntu install for dual-booting with windows. After an upgrade I attempted to install both Chrome and Brackets. The software manager rarely appears to prompt for system password when attempting to install 3rd party packages, it just sits not doing much.
On occasion after reboot I am able to install a single 3rd party package, which I get prompted for a password for, but most of the time I receive no prompt and the package install hangs. As OP notes, there is a shift in formating on the page when clicking 'install' for the first time. On occasion I am then greeted with a password input pop-up (although this has only occured with a Chrome install, and even then only after multiple reboots, I have been unable to install other 3rd party apps.) Clicking on 'install' for a second time places a 'Waiting to install' icon in the sidebar, right clicking on this icon give an empty menu, a seperator, and then a 'Lock to launcher' menu item that does not appear to do anything when clicked. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-software in Ubuntu. https://bugs.launchpad.net/bugs/1573408 Title: GNOME Software does not install third-party .deb packages Status in GNOME Software: Fix Released Status in gnome-software package in Ubuntu: Fix Released Status in gnome-software source package in Xenial: Fix Released Bug description: Impact installing local debs from nautilus doesn't work Test case download a deb and double click on it nautilus Regression potential the changes are restoring a feature that was working, should regression other parts of the code ----------------- Unlike previous versions of Ubuntu Unity, I'm unable to install the google-talk-plugin in Ubuntu 16.04, where it (the deb) can be downloaded here: https://www.google.com/tools/dlpage/hangoutplugin After downloading, I open the deb file from Firefox and it launches the gnome-software package (used in Unity now). The first time I click the install button in gnome-software, I notice a strange repositioning of the layout, but nothing else happens. Clicking the install button a second time puts a question-mark-progress-launcher onto the launcher (task) bar, but it never progresses: http://neartalk.com/ss/2016-04-22_001_1262x740.png So far, no one has offered a workaround: http://askubuntu.com/questions/760305/how-to-install-google-hangouts-plugin-in-ubuntu-16-04 ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: gnome-software 3.20.1+git20160420.1.ca63436.ubuntu-xenial-0ubuntu2 ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6 Uname: Linux 4.4.0-21-generic x86_64 ApportVersion: 2.20.1-0ubuntu2 Architecture: amd64 CurrentDesktop: Unity Date: Fri Apr 22 01:02:45 2016 InstallationDate: Installed on 2016-04-22 (0 days ago) InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1) SourcePackage: gnome-software UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/gnome-software/+bug/1573408/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp

