Can you try Ubuntu MATE 16.04 Alpha 2 in the Live session and let me know if this issue still persists? Multi monitor support was improved in MATE 1.12 which is now include in Ubuntu MATE 16.04.
Can you try Ubuntu MATE 16.04 Alpha 2 in the Live session and let me know if this issue still persists? Multi monitor support was improved in MATE 1.12 which is now include in Ubuntu MATE 16.04.