Window.RefreshRect
From Xojo Documentation
Method
Window.RefreshRect(X As Integer, Y As Integer, Width As Integer, Height As Integer[,EraseBackground as Boolean])
Supported for all project types and targets.
Supported for all project types and targets.
Repaints only the region of the window specified by the parameters X, Y, Width, and Height. X and Y are the coordinates of the top, left corner of the rectangle and Width and Height its width and height. All are in pixels.
If the optional parameter EraseBackground is True, the background will be erased prior to redrawing the area. The default is True.