^^; jimmy quick answered,, OK I go to bed. EDIT
have you tried another material preset for JS pants?
I believe you have installed them with genesis starter essential kit. (so you have js pants)
select JS pants,
then open surface tab,,
select “preset” view (now you select “edit”)
(top area of surface pane)
if you change preset, there are another material presets (with texture ).
as you know,, material preset apply texture on diffuse property.
now your diffuse texture is black,, so if you apply your color on texture as diffuse color,,
it may not clear visible.
and you can remove the texture on diffuse color property,
click small triangle, select none. it remove texture, so that you can change diffuse color
but I think you better first try with another preset and diffuse texture.
Now I apply 02_pants duf. ‘you know the texture seems like silver
then change edit mode,, apply another color as diffuse color with the texture.
Click thumbnail to see full-size image