popup does not show on second round (cf #763893)

[jpe]

I have more details on the bug #763893:

The window of popup has correct width, but 0 height on second try (clicking on tux)

This phenomenon does NOT depend on the font size used.

Description: Ubuntu 14.04.1 LTS
Release: 14.04

gnubiff (15-3)
  Depends: libc6
  Depends: libfam0
    libgamin0
  Depends: libgcc1
  Depends: libgdk-pixbuf2.0-0
  Depends: libglib2.0-0
  Depends: libgtk-3-0
  Depends: libpanel-applet-4-0
  Depends: libpango-1.0-0
  Depends: libpopt0
  Depends: libssl1.0.0
  Depends: libstdc++6
  Depends: libx11-6
  Depends: sox
 |Depends: dpkg
    dpkg:i386
  Depends: install-info
    install-info:i386
  Recommends: fam
  Conflicts: <gbiff>
  Conflicts: <gbiff:i386>
  Conflicts: <gbiff2>
  Conflicts: <gbiff2:i386>
  Replaces: <gbiff>
  Replaces: <gbiff:i386>
  Replaces: <gbiff2>
  Replaces: <gbiff2:i386>
  Conflicts: gnubiff:i386

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: gnubiff 2.2.15-3
ProcVersionSignature: Ubuntu 3.13.0-43.72-generic 3.13.11.11
Uname: Linux 3.13.0-43-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.6
Architecture: amd64
CurrentDesktop: Unity
Date: Sat Jan 3 21:22:50 2015
InstallationDate: Installed on 2015-01-02 (1 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
SourcePackage: gnubiff
UpgradeStatus: No upgrade log present (probably fresh install)

[Rolf Leggewie (r0lf)]

I believe for me, it's the other way round on bionic. The first click often results in limited height. On the second attempt, I can see the list of mail.