I thought that you would store two environments in PRStructure and
that PRPierFrame (or your custom subclass) would depending on the
context (the command) use a different one.

Thanks for idea of using overriding the behaviour in PRPierFrame - previously I'd struggled modifying environments in PRContentsWidget.

The solution I've finally arrived at is:

1) I've added a method to my custom kernel #editingEnvironment

2) I've overridden #environment in PRPierFrame so that it now reads:

environment

| environment |

(self context command isView or: [self context command isQuick]) ifTrue: [

environment := self context structure environment

] ifFalse: [

environment := self kernel editingEnvironment

^ environment

So much simpler than my other two attempts - thanks again

Nick