Cannot Create Grouped Filter (Weird AJAX Thing?)

Create a filter. In filter settings, click 'Expose this filter to visitors, to allow them to change it ' to create an exposed filter.

Then tick 'Grouped filters' under 'Filter type to expose'. Rather than give me the options for grouped filters, it resets dialogue to show the options for a non-exposed form; however, the exposed form checkbox remains checked.

Finally, if I uncheck exposed filter at this point, it returns me to the dialogue for exposed filters, but now the exposed filter checkbox is unchecked.

Thus, I cannot use grouped filters. Any idea why it's happening & what I can do about it?