Hi,
Giving a try to the current gaupol from git in a live session of Fedora 24 Workstation (from Fedora-Workstation-Live-i386-24-1.2.iso):

• Open gaupol.
• Note that, even if no documents are open, the dropmarker of the Undo button is not disabled, though the Undo button itself is disabled.
• Clicking the dropmarker triggers the next error:

File: /home/liveuser/Descargas/gaupol-0.91/gaupol/agents/menu.py
Line: 165
In: _on_undo_button_show_menu

    for i, action in enumerate(page.project.undoables):

AttributeError: 'NoneType' object has no attribute 'project'

Environment

Platform: Linux-4.5.5-300.fc24.i686-i686-with-fedora-24-Twenty_Four
Locale: es_ES.utf_8

Versions

aeidon: 0.91
chardet: 2.2.1
enchant: 1.6.6
gaupol: 0.91
gstreamer: 1.8.1.0
gtk+: 3.20.6
pygobject: 3.20.1
python: 3.5.1

I didn't try to update the system of the live session, so I don't know if the involved packages are really up-to-date.