// MTRoundRectangle clipRect = new MTRoundRectangle(x+border, y+border, z, width-(2*border), height-(2*border), arcWidth, arcHeight, applet);
MTRectangle clipRect = new MTRectangle(x+border, y+border, z, width-(2*border), height-(2*border), applet);
clipRect.setDrawSmooth(true);
clipRect.setNoStroke(true);
clipRect.setBoundsBehaviour(MTRectangle.BOUNDS_ONLY_CHECK);
this.clip = new Clip(gl, clipRect);
this.setChildClip(this.clip);
this.drawInnerBorder = true;
//Add window background
final MTRectangle windowBackGround = new MTRectangle(x, y, z, 100, 200, applet);