Feature request: trackpad / mouse mode instead of touch mode

[jorbig]

SecondScreen would become even more useful if it could offer a mouse or trackpad mode. What I mean is this: when you connect your smartphone to a second (bigger) display, the smaller phone display shouldn't be in the regular touch mode, but in trackpad mode (with a transparent/invisible and fullscreen trackpad layer activated), so that you can control the mouse on the big screen with your phone screen as a trackpad (comparable with Samsung Dex, except that the display is still mirrored). This works already in RDP sessions with Microsoft Remote Desktop (which includes its own Mouse Mode), but it would be extremely useful if we could use this trackpad mode with everything in Android.

What comes close to achieving this functionality is the third party app 'Trackpad: big phone mouse', which basically adds a transparent trackpad layer to the screen, but that app leaves annoying traces. Does anyone know a better alternative, or even better: could @farmerbb include this functionality in the SecondScreen app itself?