bad startup condition not generating message box

[JohnDMcMaster]

 ./app/argus.py 
qt5ct: using qt5ct plugin
ArgusCommon: checking threads
grbl thread updated: 139646440658752

main: got exception
Traceback (most recent call last):
  File "/home/mcmaster/doc/ext/pyuscope-rhodium/uscope/gui/gstwidget.py", line 1033, in gstwidget_main
    _mainwin = AQMainWindow(**kwargs)
  File "/home/mcmaster/doc/ext/pyuscope-rhodium/uscope/app/argus/main.py", line 182, in __init__
    self.ac = ArgusCommon(microscope_name=microscope, mw=self)
  File "/home/mcmaster/doc/ext/pyuscope-rhodium/uscope/gui/common.py", line 200, in __init__
    self.microscope = Microscope(auto=False,
  File "/home/mcmaster/doc/ext/pyuscope-rhodium/uscope/microscope.py", line 97, in __init__
    self.init(**kwargs)
  File "/home/mcmaster/doc/ext/pyuscope-rhodium/uscope/microscope.py", line 138, in init
    self.default_microscope_config(mconfig, overwrite=False)
  File "/home/mcmaster/doc/ext/pyuscope-rhodium/uscope/microscope.py", line 198, in default_microscope_config
    grbl_mconfig(mconfig, overwrite=overwrite)
  File "/home/mcmaster/doc/ext/pyuscope-rhodium/uscope/motion/grbl.py", line 2004, in grbl_mconfig
    grbl = get_grbl()
  File "/home/mcmaster/doc/ext/pyuscope-rhodium/uscope/motion/grbl.py", line 1995, in get_grbl
    return GRBL(port=port, gs=gs, reset=reset, verbose=verbose)
  File "/home/mcmaster/doc/ext/pyuscope-rhodium/uscope/motion/grbl.py", line 857, in __init__
    self.reset_probe()
  File "/home/mcmaster/doc/ext/pyuscope-rhodium/uscope/motion/grbl.py", line 911, in reset_probe
    self.gs.reset_recover()
  File "/home/mcmaster/doc/ext/pyuscope-rhodium/uscope/motion/grbl.py", line 640, in reset_recover
    raise Exception(
Exception: Timed out reestablishing communications. Limit switch? Force reboot GRBL or re-plug USB cable