OpenColorIO panel sliders readability

[Shebbe]

Grats on the release of OCIO support. 

Before release I gave some readability feedback around the state of the exposure and gamma sliders. I see some improvements have been made that aren't in release yet. But perhaps it is still unintuitive now? It is super visible that it is 'disabled' but at the same time it looks like a glitch that the elements disappear completely.

Would it be possible to just grey out the needle and text (and set it back to 0 during disabled state) rather than removing them? That should be more familiar to read and understand in my opinion.