Closing and reopening Chrome eliminated a un-clickable floating window on my mac.
The window was floating over most other windows on a 2nd monitor and was quite large. I was able to create a third desktop with the "show desktop" function, then drag my working windows to the new desktop (including the windows hidden behind the unclickable image) then I destroyed the crippled desktop by clicking on the X in the 'show desktop' header. However, a small unclickable image (with the same graphic as the problem window) remained hovering on the newly populated desktop.
I closed Chrome, and the image went away. It did not return when I reopened chrome and recovered my history.
This was Chrome Version 79.0.3945.130 (Official Build) (64-bit) on macOS Mojave 10.14.6 on 2020-02-12.