Description:
We know that in a new model a default Theme is automatically set and it is applied until it is overridden at either a Subject area or a Diagram level. However there can be situations where an existing model has various Themes applied to different Subject areas and Diagrams. Is there a way to rest the Theme globally across the model to inherit from the Default?
Solution:
Yes, the Themes can be reset globally in Model | Model properties by pressing the icon under 'Default Themes' as follows;

This would reset all existing Theme(s) in the model with the default Theme as set under Themes in Model | Model Properties. At this point you can also create a new Theme and use that across the model.