A graphical user interface for a computer program, the interface comprising an array of main panes each providing access to a particular aspect of the program, the panes being in register with one another at a vertex corresponding to the area in which all the panes meet, each of the panes being adapted to expand as a pointing device highlights a pane, the expansion of said pane relative to the other panes wherein the panes remain in register with one another at the vertex as a pane expands.