stretch/Xfce: some strings now using larger font

[Mike Kupfer <m.kupfer@acm.org>]

Last night I updated my stretch VM (VirtualBox), and I now see larger
characters in several places, including

- xfwm4 titlebar
- labels in the Xfce window buttons applet
- Xfce application menu
- Xfce logout dialog

But the Xfce settings dialogs (Appearance, Window Manager) say that the
font settings have not changed.  And the text in the Xfce terminal
emulator looks normal.

The VM was previously updated on June 1st.  It's not obvious to me from
looking at last night's list of updated/new packages what would be
causing this.

I don't see larger-than-expected characters with Cinnamon.

Is anyone else seeing this?

FWIW, the host is running Jessie, and I'm using the Debian VirtualBox
packages.

thanks,
mike