Lawrence was key in fighting for easier computer experiences where there is one interface instead of a 'backend' and 'front end'. Before Lawrence, it was common to do all your adding and editing in one 'view' or mode, and then switch to another mode to what you did. Lawrence helped merge these two worlds so you can add, edit, and view more easily.
Excerpt:
"Early in his Xerox career (he began there in 1973), Mr. Tesler and another researcher, Tim Mott, developed a program known as Gypsy, which did away with the restrictive modes that had made text editing complicated. For example, until Gypsy, most text-editing software had one mode for entering text and another for editing it."
Lawrence's contributions extended beyond modes:
"Gypsy brought to fruition the idea of opening a computer file by simply clicking on a screen icon while pointing at it with the mouse cursor. Before that, files had to be opened by typing the file name into a command line."
To emphasize Lawrence's passion and the need for change, the Times shares, "For many years the license plate on his car read, “NO MODES.” "