meld prints FIXME messages to standard error when files are identical on Ubuntu 14.04

[hakon]

The following message is printed to standard error:

FIXME: Oxygen::WidgetSizeData: unknown window type: "meldapp.GtkVBox.GtkNotebook.GtkVBox.GtkTable.GtkVBox.MsgAreaController.MsgArea"

The message is repeatedly written to stderr, the number of times depending on how long the files are.

System information:

$ lsb_release -rd
Description: Ubuntu 14.04.1 LTS
Release: 14.04
$ apt-cache policy meld
meld:
  Installed: 1.8.4-1
  Candidate: 1.8.4-1
  Version table
 *** 1.8.4-1 0
        500 http://no.archive.ubuntu.com/ubuntu/ trusty/universe i386 Packages
        100 /var/lib/dpkg/status

(Note: I have only tested this from Kubuntu)

To reproduce the error:
$ echo "1" > 1.txt
$ echo "1" > 2.txt
$ meld 1.txt 2.txt

This will produce 2 lines with the message when the user exits meld.

The message also appears when there are a large number of identical lines in the beginning of the file, such that the "change highlighting incomplete" message appears.

Expected output: None.
This error message messes up my terminal window, and gives no useful information to the user.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Rolf Leggewie (r0lf)]

I cannot reproduce this at least on bionic, so I suppose it must have been fixed. Can you verify?

[Launchpad Janitor (janitor)]

[Expired for meld (Ubuntu) because there has been no activity for 60 days.]