The model is open in read-only mode or the model you are trying to edit is not the currently active model.
The top-left corner indicates if a model is opened in read only mode, or if multiple models are opened.
Read Only - this means either:
- You only have viewing rights to the model. Contact the model owner or project administrator to ask for editing rights.
- You have opened an older version of the model. Read the article on Model Version Management for more information about model versions.
Multimodel: if you have multiple models open at once, only one of the models will be editable. Click the Multimodel button in the top-left corner to change the active model.
