Imported grids that can't be deleted

[GabrielaR]

I had an imported .ifc in my archicad which at one point I deleted because I didn't need it anymore. I deleted it from the Library and some of the parts I found on 3D and plans. Now I found I still have some grids imported from the .ifc in the elevation views that I can't delete. I can't open them in 3D or plan, or nowhere. They are in some "missing" layer, they can't be reserved, or unlocked, I can't make them disappear at all. 

When I open their settings this is what appears. But I can't make any change.

Operating system used: Windows