vinagre fullscreen mode drop-down menu is invisible

[Jonathan Kamens]

When I connect to a remote host over VNC with vinagre in fullcreen mode without scaling, it's supposed to drop down a menu when I move my mouse to the top center of the screen to allow me to exit from fullscreen mode, disconnect, etc.

If I move my mouse to the top center of the screen and leave it there for a second or two I see a hover message telling me that my mouse is over one of the buttons in that drop-down menu. If I move the mouse back and worth I see other hover messages. If I click, the button I'm supposedly hovering over activates as expected. But the button itself, indeed, the entire drop-down menu, is invisible.

I see this message in the console from which I started vinagre:

(vinagre:17013): Gtk-WARNING **: 12:32:45.786: Drawing a gadget with negative dimensions. Did you forget to allocate a size? (node box owner ViewAutoDrawer)

I suspect this is relevant!

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: vinagre 3.22.0-5
ProcVersionSignature: Ubuntu 4.15.0-34.37-generic 4.15.18
Uname: Linux 4.15.0-34-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.4
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Sat Sep 29 12:31:20 2018
InstallationDate: Installed on 2018-09-27 (2 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
SourcePackage: vinagre
UpgradeStatus: No upgrade log present (probably fresh install)