I took a quick look. To get the methods properly update and selected when modifying code, you should use the reference to the method, and the not the compiled method.

Try this:

methodsIn: composite  
composite wrapper  title: 'Methods' translated;
show: [ :wrapper |
wrapper fastList 
display: [ :aClass | aClass methods collect: [ :m | m asRingDefinition ] ];
format: [ :aCompiledMethod | aCompiledMethod selector asString ] ].
composite wrapper title:  'Script data' translated;
show: [ :wrapper |
wrapper fastList 
display: [ :aClass | aClass class methods  collect:  [ :m | m asRingDefinition ] ];
format: [ :aCompiledMethod | aCompiledMethod selector asString ] ].
composite updateOn: MethodModified from: [ SystemAnnouncer uniqueInstance ].

composite onChangeOfPort: #activePresentation act: [ :presentation | 
(presentation pane port: #activePresentation) value ifNotNil: [ :activePresentation | 
((browser paneNamed: #methods) port: #selection) value: (activePresentation defaultPane port: #selection) value ] ].

Cheers,

Doru