I'm running the jar gui in linux. Generally is seems to work ok, but the enter and shift-enter commands do not always work. I also get the Warnings/Errors listed below when I launch from the command line. System details:

Processor: Intel® Core™ i7-3517U CPU @ 1.90GHz × 4
OS: Debian GNU/Linux 9 (stretch) 64-bit
Graphics: Intel® Ivybridge Mobile

Messages on command line run:
333 X11Provider [INFO ] Starting X11 global hotkey provider
560 X11Provider [INFO ] Registering hotkey: HotKey{ctrl meta P}
1168 X11Provider [WARN ] Error: BadAccess (attempt to access private resource denied)
1169 X11Provider [WARN ] Error: BadAlloc (insufficient resources for operation)
1170 X11Provider [WARN ] Error: BadColor (invalid Colormap parameter)
1170 X11Provider [WARN ] Error: BadGC (invalid GC parameter)
1171 X11Provider [WARN ] Error: BadIDChoice (invalid resource ID chosen for this connection)
1171 X11Provider [WARN ] Error: BadName (named color or font does not exist)
1171 X11Provider [WARN ] Error: BadLength (poly request too large or internal Xlib length error)
1172 X11Provider [WARN ] Error: BadImplementation (server does not implement operation)
1172 X11Provider [WARN ] Error: 18
1173 X11Provider [WARN ] Error: 19
1173 X11Provider [WARN ] Error: 20
1174 X11Provider [WARN ] Error: 21
1174 X11Provider [WARN ] Error: 22
1175 X11Provider [WARN ] Error: 23
1175 X11Provider [WARN ] Error: 24
1176 X11Provider [WARN ] Error: 25
18499 X11Provider [WARN ] Error: 115
18500 X11Provider [WARN ] Error: 116

Am I missing a package on my system? Can't find similar situations on the discussion boards.
Thanks for any help you might provide.