RECOLOUR ARTWORK - COLOUR THEME PICKER EYEDROPPER DOES NOT WORK

Has anyone experienced this and fixed it? 

I'm on windows 10 and using most recent version of illustrator. 

Previous/correct behaviour of this tool was as follows:

You would select the vector artwork to recolour, then hit the recolour artwork option - the simplified panel, not the advanced one. From here, you could select the colour theme picker eyedropper and sample a colour from a jpg or anything on the artboard. But now, when I use that tool nothing happens, they eye dropper does not present itself, and clicking on a sample just instantly closes the panel. It feels like a definite bug. 

Really don't want to trash preferences. Any ideas before I go nuclear?