Dimension flat to screen not available

Morning all, I would like to show dimension annotations on a 3D view of the model. I like to display the following reference dimensions flat to screen but the otion is greyed out in the ‘system option’ while the assembly model is open.
image.png
image.png
I suppose I’m dealing with a ‘DimXpert model’, but I don’t know exactly what it is and how to set it.

The option is available in other assembly models I’m working with, like the following
image.png
Does anybody know how to solve the problem? Any help is really appreciated.

As far as I know, dimxpert is used for dimensioning in 3D and showing it on the drawing page. so it doesn’t matter how it looks in 3d environment.

did you try this?
2021-07-02_09-53-57.png

Yes all the dimensions I want to show are ‘Reference dimensions’ but they are not flat to screen, as the other model I have.

can you upload a file i want to see how it looks.
I use sw 2020

I sorted it out eventually.
I had to delete all the DimXpert tolerances, than it worked.
Delete_DimXpert_Tol.gif