I had the same problem. "Recent Notes" was also missing. This worked for me: Go to View/Sidebar Options and deselect Shortcuts. Go back and re-select Shortcuts. My Shortcuts and Recent Notes reappeared.
When editing a note if I place the cursor in the middle of a word then backspace ('Delete' on MacBook) to remove a letter the entire paragraph from the cursor to the end of the paragraph becomes selected. It is then deleted if I hit another key.