Hiding a slider - How?

Hey! I have been trying for quite some time now to figure out how to hide a slider after it has been shown. I've tried numerous ways but I have not found a solution yet. I would like to archive a code where the slider simply disappear if I hit the green area.

import controlP5.*;

ControlP5 cp5;

void setup() {
  size(400,400);


}

void draw() {
  fill(255,0,0);
  rect(0,0,200,100);
  fill(0,255,0);
  rect(200,0,200,100);
     if (mousePressed) {
      if (mouseX > 0 && mouseX < 200 && mouseY > 0 && mouseY < 100) {
          cp5 = new ControlP5(this);
  cp5.addSlider("slider")
  .setPosition(100,150)
  .setSize(200,30);
      }
    }

         if (mousePressed) {
      if (mouseX > 200 && mouseX < 400 && mouseY > 0 && mouseY < 100) {

      }
    }
}