Using multiple AND/OR operators in contextual filters I'm trying to query my nodes by using a contextual filter in views, however, I am unable to use multiple AND (+) operators and OR (-) operators at the same time. For example:

This works:

mysite.com/json/20
mysite.com/json/19+20


This does NOT work:

mysite.com/json/21,19+20
mysite.com/json/21+27,19+20
mysite.com/json/21+27/19+20


Using the "/" causes the additional arguments to be ignored.
What I'm trying to tell the view is to return nodes that have a Term ID equal to either 21 or 27 AND also either have a Term ID equal to 19 or 20.

Here's my view:



Here's the contextual filter:





I have tried checking the "Allow multiple values" box, but it does not affect the filter at all. Does anyone have any suggestions?
As a workaround I have second contextual filter configured and arguments are separated with "/". In this case your /21+27/19+20 should work fine. 

Still searching for the real solution.