The InteractivePlugin.isInContext should return a String instead of boolean
|Reported by:||Nicklas Nordborg||Owned by:||Nicklas Nordborg|
|Priority:||minor||Milestone:||BASE 2.0 RC2|
If so, the plugin could return null as a replacement for TRUE and a message instead of FALSE. The message should contain a description why the plugin couldn't use the item as requested. This change may also solve ticket #152.