Query Tab Coloring based on instance and database
As for now, it appears that query tab coloring only is based on instance. In smaller environments, it is not uncommon to see for instance both production, test and stage in the same instance. As for now, Query Tab Coloring does not work very well in such scenarios.
This is included in SQL Prompt 6.5 which you can download from http://www.red-gate.com/products/sql-development/sql-prompt/
@Aaron Law - that's great news. It would make this feature very useful.