Unable to close push dialog - "Could not acquire lock. Please try again later."

[GunChleoc]

I am using Ubuntu Linux and I added the xenial-proposed channel to my updates to test something. Bazaar explorer started acting up after that. I removed the channel, then uninstalled and installed bzr and Bazaar Explorer.

Now, after pushing a branch to Launchpad, the "Push" dialog remains open. After a while, I get an error message "Could not acquire lock. Please try again later."

I can hit "OK" to dismiss the error message, but I can't close the dialog. Closing by right-click from the Launcher also won't work.

While I'm waiting for a fix, what is the name of the process so I can kill it on the command line?

Another side effect of this update is that when clicking "Commit" and then "Diff", when I close the Diff, Bazaar Explorer will hang. "Could not acquire lock. Please try again later." is also displayed. I can kill that one from the Launcher. I don't know if this is the same bug or not.

ETA: The "Add" button also crashes/hands Bazaar Explorer. So, this might be a general problem with dialog windows.