I am switching the edit mode from visual editor to source code, and it still freezed the tab like the screenshot. I can't save my work in any way?

Thanks for taking the time to report this!

What are exact steps to reproduce the problem, so that anybody else could try? Also see https://www.mediawiki.org/wiki/How_to_report_a_bug

Oh... I am not sure, I used firefox and OSX Yosemite. I put the OS X into sleep for a night, and when I return to the browser then it got into this situation.

Is this the same as T41057: VisualEditor: Error message texts when the Parsoid service is not around aren't very clear, should be improved? Also, do you remember whether you copied and pasted a reference?

Frankly, I am not sure whether it's the same with T104230 I will give you feedback if I encounter this situation again next time.

In T100136#1509579, @Shangkuanlc wrote:

Frankly, I am not sure whether it's the same with T104230 I will give you feedback if I encounter this situation again next time.

Thank you!