I have a project that requires the use of a tablet (i.e. no physical keyboard or mouse).  It is reliant on touchscreen and the on-screen keyboard (OSK).  The tablet is also connected to a television via HDMI.

Funny thing about Windows 10.  If I am in “Tablet Mode” and plug in an HDMI, it kicks me out to “Desktop Mode”.  It means I lose things like certain gestures, the fullscreen Start Menu, and even the OSK.

Surprisingly, there is no easy UWP/C# calls to make to activate the OSK when a TextBox gets focus.  Although there is a keyboard icon in the System Tray, it is not usable because my application is fullscreen, so it hides the whole Taskbar.  The only solutions I had found required building a custom keyboard from the ground-up and calling into “osk.exe”, but doing that opens a windowed version of the OSK, which becomes a pain to work with via touchscreen.

Finally, I came across a solution that seems reasonable at this juncture.  Turns out that there is a setting that will popup the OSK when in “Desktop Mode” and when no physical keyboard is detected.  Came across the solution here:

http://www.windowscentral.com/auto-display-touch-keyboard-windows-10-desktop-mode

For 2-in-1s, flipping the keyboard all the way back typically triggers the “no physical keyboard found” event.