操作系统：Mac OS X
NW.js版本（最新0.20，尝试从0.14到最新）
Issue:
Application freezes(UI becomes unresponsive) after doing following steps:
- Open application
- Use functionality which trigger code "window.print()", print dialog comes up. User may print/cancel it.
- Keep application idle for some time(3-5 mins) and now app freezes(Rendered process freezes and UI becomes unresponsive).
Nw.js论坛上提出的问题： https://github.com/nwjs/nw.js/issues/5020
有人遇到过这样的问题吗？有关排除此类问题的任何提示吗？