[rules-dev] Drools debugging issue: drl error message are no longer displayed

Started using Drools (Expert) in our company a few weeks ago. At the beginning I was able to see detailed error descriptions for the DRL's I was writing, which assisted in resolving bugs. Fairly quickly these messages have disappeared and I found myself with viewing the rete tree alone as a method of verifying the rule and debugging (which doesn't assist in understanding where the problems is). Any idea why do the error detailed message disappear and how to return them? I am using Eclipse 3.5.1 and Drools 5.1.1 Thanks Hezi