Apparently, Unity 2D is no longer available after upgrade to 14.04. So the Radeon Xpress 200M video chip from nx6325 don't support the resolution 1366 x 768 (16: 9) with Unity 3D. If anyone can include Unity 2D to 14.04 release, please help me. For now, the only solution to use 1366 x 768 resolution on the second monitor is login Ubuntu in metacity mode.
Apparently, Unity 2D is no longer available after upgrade to 14.04. So the Radeon Xpress 200M video chip from nx6325 don't support the resolution 1366 x 768 (16: 9) with Unity 3D. If anyone can include Unity 2D to 14.04 release, please help me. For now, the only solution to use 1366 x 768 resolution on the second monitor is login Ubuntu in metacity mode.