🚀 go-pugleaf

Using xbfe 0.5, the program dies with the following:
X Error of failed request:  BadMatch (invalid parameter attributes)
  Major opcode of failed request:  67 (X_PolyRectangle)
  Serial number of failed request:  10159
  Current serial number in output stream:  10160

The problem occurs when I click button1, and then move the cursor
(i.e. when AdjustSelection is triggered.) I did not install X here,
and know little about X, so I don't know if this is an X problem or a
GNU problem. I have tried compiling xbfe with gcc 2.3.1 and the older
version of gcc installed here which reports itself as:
gcc version 1.96 (88open OCS/BCS, DG-1.96.4, Jan 17 1992)

I am on a DGUX 5.4.1 Aviion workstation, using X11R4 (compiled with I
don't know what)
This happens no matter what font file I try to edit.

Is this an X error or an Xbfe problem? If it is an X error, where can
I look to find out how to fix it/work around it?

Thanks for any help, 
Eric