Gtk-CRITICAL GTK_IS_INVISIBLE (widget)' failed error

I’ve just downloaded & imaged the Ubuntu MATE 15.10 Raspberry Pi image & after running apt-get update && apt-get upgrade to update everything, the first thing that I did was to install TransGUI, using apt-get install transgui. It won’t run from a shortcut, & if I try to run it from a terminal it loops on this line:

(transgui:1396): Gtk-CRITICAL **: IA__gtk_widget_realize: assertion 'GTK_WIDGET_ANCHORED (widget) || GTK_IS_INVISIBLE (widget)' failed

Following on from some Google searches, I have tried changing my theme from GTK+ to Plastique, & then to each of the other choices, but nothing has made a difference. All the other software that I’ve tried to run afterwards, such as Firefox, LibreOffice, VLC or OMXplayer seems to work beautifully though. What can I do to sort TransGUI out please?

Thanks, Justin

You should raise this with the transgui developer(s).