Determines whether the gutter's image is rendered directly to the window or painted to an in-memory bitmap first.
property DoubleBufered: Boolean;
When DoubleBuffered is False, the gutter paints itself directly to the window. When DoubleBuffered is True, the gutter paints itself to an in-memory bitmap that is then used to paint the window. Double buffering reduces the amount of flicker when the control repaints, but is more memory intensive. Only rectangle of the gutter for the currently painted line is buffered. This allows to reduce memory usage when DoubleBuffered is True.