If you downloaded DisplayFusion 12.0 and are having issues with languages please re-download and re-install. We have repacked the release as 12.0c with the languages fixed.
I am using DisplayFusion v4.0.1 Beta 3. If I open NP++ and move it to my secondary monitor and then close it on my secondary monitor, on re opening it opens briefly on my secondary monitor and then DF moves it to my primary monitor. If I shut down DF this does not occur and it opens in the last position which is on my secondary monitor.
Are you launching it from the Start menu? If so, could you try disabling the "Launch Start Menu shortcuts on current monitor" option on the DisplayFusion Settings > Taskbar tab?
