(Processing) PGraphics doesn't update when all pixels copied from another PGraphics

I have a small problem with PGraphics. I have folowing piece of code extracted from larger project I am working on:

int x=0;
int y=0;

PGraphics array1;
PGraphics array2;

void setup() {
  size(200,200);
  background(0);
  array1 = createGraphics(200,200);
  array2 = createGraphics(200,200);
  frameRate(10);
}

void draw() {
  array1.beginDraw();
  array1.background(0);
  array1.noStroke();
  array1.fill(150);
  array1.ellipse(x,y,20,20);
  array1.endDraw();

  array1.loadPixels();
  array2.loadPixels();

  //presence of two below lines doesn't change anything
  array1.updatePixels();
  array2.updatePixels();

  //not by arrayCopy since I want to add filters in next project
  for(int i=0; i<200*200; i++) {
    array2.pixels[i] = array1.pixels[i];
  }

  //presence of two below lines doesn't change anything
  array1.updatePixels();
  array2.updatePixels();

  //I want to see only the array2 - now it should be the same as array1
//  image(array1, 0,0);
  image(array2, 0,0);

  //presence of two below lines doesn't change anything
  array1.updatePixels();
  array2.updatePixels();

  x++;
  y++;

}

In general I want to copy PGraphics array1 into PGraphics array2. However the array2 looks like the array1 in the first frame and the visual doesn't update. When I have added:

println(array1.pixels[0]+" "+array2.pixels[0]);

it prints:

...
-6908266 -6908266
-6908266 -6908266
-6908266 -6908266
-16777216 -16777216
-16777216 -16777216
...

So obviously both arrays contain the same value. I have no idea why I can't see the updated array2.

Following the docs I tried the updatePixels method placed in different places and this doesn't help.

What I am missing?

Thanks in advance!

You forgot to call beginDraw() and endDraw() for array2 PGraphic. If you do:

array2.beginDraw(); // HERE!!
  for (int i= 0; i<array1.pixels.length; i++) {
    array2.pixels[i] = array1.pixels[i];
  }
  array2.updatePixels();
array2.endDraw(); // and HERE!! :)

it should work as expected.