run arduboy.fillRect error

[piaoxuebingfeng]

run code at release V0.7.8 error

when i create a project,i write code :

#include <Arduboy2.h>

Arduboy2 arduboy;


void setup() {
  arduboy.begin();

  // default 60 and it saves us battery life
  arduboy.setFrameRate(15);
}

void loop() {
  if (!(arduboy.nextFrame()))
    return;

  arduboy.clear();
  arduboy.setCursor(4, 9);

  arduboy.print(F("Hello, world!"));
  arduboy.fillRect(10, 10, 4, 4, WHITE);
  arduboy.display();
}

i got some errors

TypeError:Cannot set property 'title' of underfined. how can i solve the problem.