#6903 EditorType support 'hideDecorationOnEmptyLine'

As soon as many decorations are not defined in the resource editor and are also not defined, it can become confusing. To prevent this, undefined decorations (EmptyLine) can be combined into one.

This is done in the EditorType via the StyledPropertyConfig:





This can be used, for example, if the events for a transition are decorated on the state in a statemachine.
As the decorations are generated via the domain diagram, there are no disadvantages.

On github the example has been extended:
​https://github.com/actifsource/ch.actifsource.example.editortype