I'm having problems with Processing 2.0b3 using beginDraw with two offscreen PGraphics objects at the same time. A sample program is below. The reason I get this situation is actually that I have one offscreen buffer that is worked on in draw() and another that is worked on by captureEvent(). This code works fine in Processing 1.5.1; and I see in the Processing source code for opengl/PGraphicsOpenGL.java  where this error seems to be coming from; but is it really not possible any more to have rendering to two different offscreen buffers overlap?

PGraphics pg;
PGraphics opg;


void setup() {
  size(100, 100, P2D);
  pg = createGraphics(80, 80, P2D);
  opg = createGraphics(80, 80, P2D);
  pg.beginDraw();
  pg.background(102);
  pg.stroke(255);
  
  opg.beginDraw();
  opg.background(102);
  opg.stroke(255);
  opg.line(20, 20, 80, 80);
  opg.endDraw();
  
  pg.line(20, 20, 80, 80);
  pg.image(opg, 50, 50);
  pg.endDraw();
  noLoop();
}

void draw() {
  image(pg, 10, 10); 
}