In bpmn2 there is a visual notation of the default sequence flow, for example see: http://imgur.com/a/6RBxD (little slash mark one the "else" flow)

In the DefaultRoute property selector we should possibly show the conditional expression if one exists, then sequence flow name if one exists and the connecting node name as the last resort as they may change many times during modeling of the process.

This property was initially on the sequence flow level and we moved it to the gateway properties in jbpm designer but we should check with the ux team because the ideal scenario would be for users to make this selection as they are entering the condition expression on the gateway itself (maybe a checkbox or something similar). Adding the slash to display the default connector or even a color display would be a nice improvement.