A Puzzlement

When one clicks on a window (like a Word doc or a new email) and then starts to type while the computer is still processing, the text doesn't appear. Once a person re-selects the window/text box/document and starts to type again, the text appears. What puzzles me is this...where does that first text go? Is there like a magic hidden folder somewhere that contains all of those random letters that never made it on the page? It is indeed a puzzlement.