[galaxy-dev] understanding change of colours in history

Hi, Can someone point me in the direction of where the code in Galaxy is called to change the history background for example when a job changes from Yellow to red on error, or yellow to green on success. I've been going around in circles now trying to figure out, how this is implemented and how the labels are updated on the history. Also, If I change history_common.mako file and I restart the system my changes aren't seen (i.e. add a new icon if the system goes into error) Thanks for any insight Neil