Color of lines cant be changed

Hei

I got a DWG file that I have to modify. I have a problem whith some lines, all which lines I have set to white/black in the layer manager. Some lines changes color, some just dont. I cant change the color, not by the layer manager, or the property setting (set line color to follow layer or change it for any color..)

it seems the lines that cant be changed are in blocks. How can I change line colors of entities contained in larger blocks?

I'm using the free DraftSight version V1R5 x64 on a 64bit Windows 8 machine