Simple Filter: Change Site Keep Variable

[AmberSJones]

Would it be possible to change the site in the simple filter but keep the variable? If so, we should make that the default behavior. Currently when the site is switched in the filter, the variable defaults to the first variable in the list at that site. Also, when 'Site' is unchecked, 'Variable' get reset.

[horsburgh]

Moved this to low priority. It might be confusing for users, but is technically functional right now. We may want to rethink the way this works a little later.