Unable to Switch Dimension Style

[rhettinger]

I need to delete this dimension style from a project. So far I have selected the used dimensions and switched them to another style. But there are still 8 left that will not let me switch. The type properties is greyed out and the drop down dialog box gives me a clue that they are "constraints".

I am unable to select the dimensions that are being used by the (8) constraints. I am unfamiliar with what the constraints are or how to find them so I can switch them to another style. How can I find and delete/switch these so I can purge this dimension style from the project?

[RobDraw]

Maybe contained in families?

[BDMackey]

Unless you are in Revit 23 when using select all it doesn't go into legend views for selection. So if those are used there then you will have to hunt them down and manually change them there.  Although I don't think that is the issue here as you are getting the constraints selection.