Window disappears when left shift button is pressed
Every time I use the left shift key on my 2017 MacBook Air, the window that I'm on disappears. The letter I want to capitalize does get capitalized but I have to push shift again for the window to appear. The right shift key doesn't do it. I've gone into system preferences and set the keyboard back to default settings and that didn't work. Any suggestions?
Thank you in advance!
MacBook