SQL Server Management Studio 2016

I'm having a strange problem with my SSMS 2016. Within the query window backspace, del, up, down, left, right keys have stopped working. When I reset my environment settings with "Import and Export Settings" to default setting it works but the changes don't persist when I exit the SSMS client. Every time I launch SSMS 2016 I have to do this exercise.

I also have SSMS 2014 on the same system, which works with out any problem, I tried to uninstall and install the SSMS 16 client but no luck.

Any one having the same problem?

Help please, how can I uninstall SQL Server Management Studio 2016 completely?

This happened in SSMS 2017. There was a pop-under "Add table to view" dialog that I didn't know about.
When I went to close SSMS it warned me about the dialog (which I could not close/cancel), then gave me an ugly exception about protected memory.

After restarting SSMS it all worked again.

StackExchange Database Administrators Q#142769, answer score: 4