Draftsight - Unable to create new layers

Hello everyone,

I am having an issue with a drawing within Draftsight. I cannot seem to create new layers within the layer manager. I'm pretty sure the issue is with the actual drawing I am using because I do not have the same issue with a different drawing file. Is the issue potentially that the layer manager is locked? 

 

I also cannot alter the printsyle colour. It is greyed out in the layer manager. I do not have much knowledge when it comes to printstyles so any help would be appreciated.

Thanks everyone