Weird console log output

Since moving to x3.1 or about a few weeks ago, I've started getting this 
message on the debug console log window:

Day Mon dd hh:mm:ss host.local prog[pid] <Error>: CGContextSetStyle: 
invalid context


Where

   Day       = day name abbr.
   Mon       = month abbr.
   dd        = day number
   hh:mm:ss  = timestamp 24h
   host      = local system name
   prog      = executable name
   pid       = process id

but no where in my code have I called this method.

Any ideas what this is?
-- 
/los "I was a teenage net-random"