As a result the next keystrokes you make won’t be where the end of the line you were finishing is but wherever in the body of text the cursor moved as a result of the keystroke. It’s natural for your hands to either rest on or brush the palmrest of your laptop while you’re typing but errant brushes will often register as a tap. Trackpads might be a very clever way to pack a mouse into a laptop palm rest but for years and years they’ve been a huge pain to use on account of their proximity to your palms and how sensitive they are.
