app/views/data_objects/_group_by.html.erb
<%= select_tag "view_options[group_by]", options_for_select(@group_by_options, @selected_by) %>
<%#= observe_field('view_options_group_by',
url: { controller: :data_objects,
action: :index,
layout: false},
method: :get,
with: "'group_by=' + escape(value) + '&group_type=' + \'#{@selected_type.second}\'",
on: "change") %>