Disable on screen keyboard on Pop!_OS
Originally, a gnome shell bug was reported about Caribou's on-screen keyboard popping up when just touching various non-text input elements. It seems like a patch has been implemented to resolve it, because Gnome 3.30.1 does not illustrate the reported issue. However, the default settings for the on-screen keyboard is to appear whenever touching a text input or touching an icon that receives text input e.g. terminal and text editor.
I have no use for the on-screen keyboard at all. There is no way to disable it within the settings for Pop!_OS 18.10. The only solution for disabling the caribou on-screen keyboard is through the block-caribou gnome extensions. The gnome extension is not straight forward. The gnome extension requires the Gnome shell integration Chrome extension. After the chrome extension is installed, you can search for the block caribou gnome extension, install it, and then enable it.