Something wrong happened when i use the function background in draw function and the background cover always my p5 sliders.

import controlP5.*;

ControlP5 cp5;
int value=0;
void setup ()
{
 size( 300, 300 );
  cp5 = new ControlP5( this );
 cp5.addSlider( "slider1", 0, 100, 50, 0, 0, width, 200 );


}

void draw ()
{
background(value);

}

void slider1 ( int value )
{
 // put code for slider 1 here
 println( "1 " + value );
}