Identify (and disable) on-screen keyboard

Solution 1:

That is the Steam controller keyboard. See this link for a few options how to disable it: https://steamcommunity.com/app/353370/discussions/0/358415738183388695/

Some of the posted suggestions:

• In your Steam window: View ----> Settings ----> Controller ----> Desktop Configuration. This will open a window that displays your controller. Click the box on the bottom left showing the various Arrow Keys. It will show a few settings. On the right, click on "Show Keyboard" under the "Click Action" setting. This will open up a keyboard and mouse with a bunch of possible bindings. Click the "Remove" button, below the keyboard display. Back out of the settings and click 'OK This will unbind the stupid keyboard from popping up when you press down on the stick.
• Go into your Steam settings, and under "In-game" uncheck the box that says "Use the Big Picture Mode overlay when using a Steam Controller from the desktop" Then, always launch [your game] from the desktop.
• If you'd like to get rid of this, go to [your game] in your steam Library, then right click on it and go to properties. At the bottom left you'll see "Set launch options..." open that and then add in -NoKeyboardUI. Press ok and play [your game] as you normally would. This will revert it back to the normal chat box.