Client stops reporting status, no purple

In Bigbrother, when the client software stopped reporting, the
disk,cpu,msgs, etc..  columns would turn to purple after 30 minutes if
it did not receive any updates.  

In Hobbit, the columns just turn into a - (dash).  What setting do I
need to put to make them turn purple when the Hobbit server doesn't hear
from the client?

Thanks,
Michael