Belatedly...
> Does the 'Recheck Sync' button in the view header do it?
Yes - thanks. I had been searching on the device right-click menu, where Sync Now appears but oddly Recheck Sync does not. Recheck Sync did not appear in the View - the device was not selected in the tree. Now the device is selected, it does show.
> How are you changing device files while the device is plugged in?
Sorry, I don't have a record of that.