An off-topic PS: Thunar 1.6.3

[Ralf Mardorf]

I usually use a terminal emulation (roxterm instead of xfce4-terminal)
instead of a file browser. It happens seldom that I use a file manger,
but if I need one, I more often use Xfe instead of Thunar.

So as a temporarily workaround consider to use Xfe.

Ubuntu provides a German Wiki about Xfe: http://wiki.ubuntuusers.de/XFE

I neither use a *buntu, nor did I read the Wiki ;).

Another temporarily workaround might be usage of Midnight Commander and
assumed you want to mount drives by a mouse click, than perhaps Rodent
is what you want. Rodent by the way can mount drives by a click, without
the need to have the ugly, bad and broken gvfs installed and IIRC RMS
[1] contributes to it and/or is an user, but regarding RMS I might
be mistaken.

[1]
https://www.fsf.org/blogs/rms/ubuntu-spyware-what-to-do
https://en.wikipedia.org/wiki/Richard_Stallman