Hi there,
Renoise 3.0 has less built-in interface textures than Renoise 2.8.2. I find it a little dumb. Why reduce the number of the textures if those old ones do their job well? I strongly suggest to reintroduce all the missing textures into a new Renoise version and add some more! Never cut it down if it works! Always push it forward instead!
Sincerely,
Artur 