While I have pretty much chalked this up to a MSFT Windows 8.1 issue but am interested in hearing what are your experiences with using a second monitor. When in the office I plug in, via VGA, a 1920x1080 LCD and USB mouse and keyboard (via USB hub). The 150% that I use for the SP3 native is HUGE when I go to my secondary display. I then have to mess with the scaling and make it 100% or in my case a compromise of 125% for when I whip off to a meeting and take my SP3 with me the display scaling is so small that I find it hard to use and have to re-configure every time I re-connect or disconnect. the "Let me choose one scaling level for all my displays" is UN-Checked; but does nothing much.