Whener i click anywhere in the document i get a dense grid like thing. its like Black & White pixels. if i click again it reveals some part of the document & rest of the document remains the same. Then i have to either close the document or skip to any other page to read it. also i cant copy any content because as soon as i click anywhere it shows those pixels. Attached image. this happens with every document. i re-installed Adobe Reader DC, but problem remains.