I am an Indian passport holder, living in the US (with work visa, no green card).
I had a Schengen visa issued by the Netherlands valid from 12th January, 2017 to 11th January, 2019 and spent 69 days between 28th August, 2017 to 10th November, 2017 in Schengen.
I had to visit Portugal in December and I applied and was given another Schengen visa issued by Portugal, valid from 10th December, 2017 to 10th December, 2018. So, they are overlapping.
I realize I am not allowed to have two overlapping Schengen visas in the same passport, but since I do have it, can I stay more than 21 days using the Portugal visa from December to February 2018?