Set a depth-stencil state that tests, writes, but trivially passes

* Occlusion queries seem to be unhappy with a depth-stencil state that
  performs no tests and sometimes can produce incorrect results. This
  appears to make the queries more reliable and fixed cases where depth
  clip was showing as discarding pixels incorrectly.
* There's still something weird going on here, I'm not super happy with it.
Bake in range-select min and max when opening a pixel history view

* I'm not sure if this 'hidden' latched UI state is good or bad, but it
  means the colours are visible if you've adjusted the range way outside
  of 0-1.