I am manually configuring the colors of my PowerShell and I am curious what a "popup" is and how I can see it? As of now it seems that only "Selected Screen Colors" changes anything. How might I cause an example of such a popup to appear so that I can see the color changes that I have made?
The setting is from conhost.exe which is the terminal that shells like cmd and PowerShell connect to. I don't know if there are any popups in PowerShell but by default in cmd when pressing F7 in you'll see a popup window that shows command history. You can also try F2, F4 and F9
Here's an example of pressing F7 in cmd (left) and in cmd running inside PowerShell (right)
You can show the history popup in PowerShell by temporarily unloading the PSReadLine module with
Remove-Module -Name PSReadLine
Apparently it's a terminal feature, not shell, therefore it doesn't work when nesting lots of shell levels or when changing to another unsupported terminal. Windows Terminal supports it for backward compatibility, but will display it differently. Same to the famous cmder terminal
This particular feature is not provided by Cmd – it's actually provided by Conhost, the program that draws the 'legacy' console window (and is still involved behind the scenes even if you're using Windows Terminal, although it's known as OpenConsole.exe in that situation). Conhost provides line-editing, history, and alias ("doskey") features for all programs that take line-based input (aka "cooked mode" in Unix terms).