Eydropper/color picker doesn't work outside Gimp

[Bill H]

In GIMP 1.x, and supposedly still in 2.10, the "monitor" icon in the color picker window enables an eyedropper tool which collects color info from anywhere on the screen, not just in GIMP.  This is VERY useful!  But in 2.10 it doesn't seem to work, unless I'm doing something wrong: as soon as the cursor leaves the GIMP window it reverts to Windows' generic arrowhead, and clicking anywhere outside the GIMP window just brings the new window to the front, like with any other cursor.

Or is there a step I'm missing?