Shortcut key to toggle focus between find window and main window

[DecapitatedKneecap]

I am trying to build a find string consisting of a combination of characters in different location in a text file. I will copy one character, hit CTRL+F/H to open find window, paste the character in the box, and then go back to the text file to copy another character and repeat the process. Is there a keyboard shortcut to toggle focus back to the main window so that I don't have to use the mouse to click the window?

btw the issue creation page doesn't have any fields to specify bug report, feature request, or question. It's just a title and a body.