I'm seeing an issue where Firefox addons with a button in toolbar can't be used if the addon contains text fields for passwords. These same addons work fine on my Windows machine, so I believe the issue is somehow connected to Firefox on Ubuntu.
I have several addons in toolbar, and all of them work fine except for those that require a login. When I click on a broken addon, its window opens briefly then immediately disappears, making it impossible to login.
One of my misbehaving addons is for a password manager. Because this addon is made available through the Firefox sidebar tool, I can use the sidebar to login. Once logged in, the toolbar piece of the addon works just fine.
Addons that require a username and password to log in have interesting behavior. If I click in the username text field, I can add text, but the moment I click in the password field, the window closes. I have other addons that have fields for text entry, but none of those fields asks for a password, and they work fine.
To address this problem, I've tried purging Firefox and deleting all config files. I reinstalled only one addon, one of the misbehaving ones, and it still exhibits the same problem.
I'm completely stumped on troubleshooting steps. Where should I look to find more information about what could be the source of this problem.