Replace `Extract Level` with `Extract Block` in the common filters
There are a couple of problems with this filter as is. First, the icon clearly suggests that it should be able to invert the
Group Datasets filter, which has the similar icon . However, these filters cannot inverse each other. If you group some input with
Group Datasets, the
Extract Level filter is still grayed out. In fact, in over 15 years of using ParaView, I cannot recall a single dataset I had or generated that worked with this filter. I think it's safe to say that this is not a "common" filter.
Extract Level filter should be replaced with the
Extract Block. The
Extract Block filter is much more general and able to pull blocks out of any multi-block data set. This makes it much more appropriate for the common filters toolbar. First, it is actually a common operation. Second, it can do the implied inversion of the
Group Datasets filter.