Caja-dropbox does not start on 18.04.1 LTS upgraded from 16.04.5 LTS

[Norbert]

Steps to reproduce:
1. Have Ubuntu 16.04.5 LTS with `ubuntu-mate-desktop` and `caja-dropbox` installed
2. Upgrade it with `do-release-upgrade -d` to 18.04.1 LTS
3. Reboot after upgrade to new system, login and get no Dropbox icon in the tray.
4. Remove DropBox from the system (as in https://ubuntu-mate.community/t/problems-with-the-dropbox-icon-in-the-panel-um-18-04-1/17495/6 ):

killall dropbox
sudo apt-get purge caja-dropbox
rm -rf ~/.dropbox
sudo apt-get install caja-dropbox

5. Reboot and log-in again, still no DropBox icon.
6. Try to launch DropBox from terminal with `caja-dropbox start` and get the following output in the terminal (as in https://ubuntu-mate.community/t/problems-with-the-dropbox-icon-in-the-panel-um-18-04-1/17495/7):

$ caja-dropbox start
Starting Dropbox...dropbox: locating interpreter
dropbox: logging to /tmp/dropbox-antifreeze-YXAa3r
dropbox: initializing
dropbox: initializing python 3.5.4
dropbox: setting program path '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/dropbox'
dropbox: setting home path '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90'
dropbox: setting python path '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90:/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/python-packages-35.zip'
dropbox: python initialized
dropbox: running dropbox
dropbox: setting args
dropbox: applying overrides
dropbox: running main script
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/cryptography.hazmat.bindings._constant_time.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/cryptography.hazmat.bindings._openssl.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/cryptography.hazmat.bindings._padding.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/psutil._psutil_linux.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/psutil._psutil_posix.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/linuxffi.pthread._linuxffi_pthread.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/linuxffi.fcntl._linuxffi_fcntl.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/linuxffi.sys.compiled._linuxffi_sys.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/tornado.speedups.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/cpuid.compiled._cpuid.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/linuxffi.resolv.compiled._linuxffi_resolv.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/posixffi.libc._posixffi_libc.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/librsyncffi.compiled._librsyncffi.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/PyQt5.QtWebKit.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/PyQt5.QtCore.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/PyQt5.QtNetwork.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/PyQt5.QtGui.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/PyQt5.QtWebKitWidgets.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/PyQt5.QtWidgets.cpython-35m-x86_64-linux-gnu.so'
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/PyQt5.QtPrintSupport.cpython-35m-x86_64-linux-gnu.so'
Dropbox isn't running!
Done!
xenial@xenial-vb:~$ Gtk-Message: 15:44:51.977: Failed to load module "topmenu-gtk-module"
dropbox: load fq extension '/var/lib/dropbox/.dropbox-dist/dropbox-lnx.x86_64-54.4.90/PyQt5.QtDBus.cpython-35m-x86_64-linux-gnu.so'

(dropbox:2153): GLib-GObject-WARNING **: 15:44:52.271: cannot register existing type 'GdkDisplayManager'

(dropbox:2153): GLib-CRITICAL **: 15:44:52.271: g_once_init_leave: assertion 'result != 0' failed

(dropbox:2153): GLib-GObject-CRITICAL **: 15:44:52.271: g_object_new_with_properties: assertion 'G_TYPE_IS_OBJECT (object_type)' failed

Expected results: `caja-dropbox` works after upgrading from 16.04.5 LTS to 18.04.1 LTS.

Actual results: `caja-dropbox` does not work after upgrading from 16.04.5 LTS to 18.04.1 LTS.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: caja-dropbox 1.20.0-2
ProcVersionSignature: Ubuntu 4.15.0-29.31-generic 4.15.18
Uname: Linux 4.15.0-29-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
CurrentDesktop: MATE
Date: Mon Aug 6 15:45:00 2018
InstallationDate: Installed on 2018-01-04 (213 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
SourcePackage: caja-dropbox
UpgradeStatus: Upgraded to bionic on 2018-08-06 (0 days ago)

[Launchpad Janitor (janitor)]

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

[Andis (andis-lazdins)]

I can confirm this issue. I also upgraded from 16.04 to 18.04 and instead of Dropbox icon I have now question mark without dropbox menu. I also can't start dropbox from application menu using command dbus-launch caja-dropbox start -i. It only starts with ~/bin/dropbox.py start command, which I found in another web page.
It is especially nasty because dropbox sent notification that only Ext4 will be supported starting with November and I have dropbox files on Ntfs partition and there is no way to change settings without GUI. I would be very thankful for recommendation on how to change dropbox settings in this situation.

[APolihron (apolitech)]

The problem is that 16.04 was on gtk 2 and 18.04.x is on gtk 3. I will mark this as invalid because there is no proper fix beside removing and reinstalling the dropbox applet.

[APolihron (apolitech)]

https://ubuntu-mate.community/t/problems-with-the-dropbox-icon-in-the-panel-um-18-04-1/17495/11?u=apolihronhere you will find a workaround.

[Richard Lamont (richard-lamont)]

I've seen a couple of other applications which produce the message: Failed to load module "topmenu-gtk-module"

This appears to be a problem with dist-upgrading ubuntu-mate-default-settings from 16.04 to 18.04. The upgrade installs /etc/X11/Xsession.d/80mate-environment but does not remove the older /etc/X11/Xsession.d/99mate-environment. Deleting the latter fixed the problem.

[Launchpad Janitor (janitor)]

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