[scribus] UHD monitor problems

[John Jason Jordan]

I have a brand new laptop with a 4K screen (3840x2160), on which I use
Xfce 4.12 on Xubuntu 18.04, up to date. 

The version of Scribus is 1.5.3. However, Scribus is unusable because
at the top of the document window I see:

FileEditItemInsertPageTableExtrasViewScripterWindowHelp

In a font that is about 1.5mm high. Worse, if I click on any of them
the menu is blank, completely missing. If I open a toolbar the font in
the toolbar is OK, but the title at the top of the toolbar is in the
same tiny size. 

I thought I'd look into Preferences to see if I could fix this, but I
can't get into Preferences because the menus are all missing. I've had
to fix an occasional minor item in other applications, but nothing like
this.

Any suggestions?