"Interactive refinement level" goes above available refinement levels.
In the renderers' variable tab, there are controls of the variable, including a "Ref Level." These levels are from 0 to a positive number, for example, 3 in the Katrnia data set.
On the top right menu, there's an option to control "Interactive refinement level." It shows level numbers from 0 to 9, regardless of what the range is in the previously described "Ref Level" control.
This mismatch confuses users...
Update on 4/4/2018: This bug is still there...
No longer relevant.
It seems the confusing control, i.e., the "Interactive refinement level" control on top right, is still there, and has nothing to do with VDC levels. In fact, that "Interactive refinement level" control is even there with a native NetCDF file.
Reopening. Just to clarify, the 'interactive refinement control' is on the menu bar, not the variable's tab.
@sgpearse this is not a high priority but, and I'm guessing we're not going to fix it for 3.6. So I'd suggest not advancing it to the next round of bug verification.