In Revit®, you can use Design Options to create model variations that you can present to a client. To find more information on Design options, go here.
If you hover over items in your Revit® model and you are not able to select (some) of your items this can be due to design options created by the designer. Design options can be viewed in the ”Manage” tab in the “Design Options” area.
In the video below you see how a design option is selected, and after this change, the items belonging to this design option are then selectable and editable.
Link models are models when individual buildings or different parts of a large building reside in separate project files, or when each discipline works in its own edition of a building model.
To see if your model contains Linked models, you can go to the “Manage” tab in the “Manage project” area. If you click there on “Manage Links“, then you will see the window for all the linked models in that Revit® model.
In the video below, you will see the overview of linked models. If you want to edit things inside that model, you’ll have to open that model in Revit®.