Hello... I have a CScrollView that displays a bitmap and I'm trying to draw a grid that I can turn off and on by check box and when the mouse is over a section of the grid that square highlights... I do all the drawing in the ondraw function... But when I have many grid squares it becomes slow to scroll and to highlight the square the mouse is over... I'm not sure the best way to go about this and where to place code to speed it up... The bitmap is only loaded once... But in ondraw the grid has to redraw every time scrolled and when mouse moved over a square.. In onmousemove I call invalidate so the square under mouse changes... Thx for any ideas can give me... Tc always