Shift keys won't select multiple items.
My Shift keys have stopped selecting multiple items in list view. I updated to Sierra about a week or so ago, and guessing it might be related to that. I'm having this problem on both my laptop keyboard and the external keyboard connected to it. I'm unable to select two items whether they are next to each other on the list or far apart. Command-A does work to select everything so this appears to be strictly a shift key issue.
I'm also having a selection problem when I try to use the Shift key with tools in Photoshop, which I suspect is a result of this. Even using the Wacom pen to select text for copy/paste has become problematic. So overall it seems to be a selection problem, with the Shift keys being the specific point of pain. I've run First Aid to clean out any glitches but am at a loss as to what else to try. Any thoughts?
MacBook Pro (Retina, Mid 2012)
2.7 GHz Intel Core i7
16 GB 1600 MHz DDR3
MacOS Sierra 10.12.2
Adobe Photoshop CS6