Nearly not responding when editing on a very big file

[greenlaw110]

On a file with a java code block over 8000 lines, typing one character takes up to 2 seconds to get it reflected on screen on my i7/16G RAM/ssd machine

The other thing is when I first load that big file, even after the Editor.prototype.changed get triggered, it takes up to 4 seconds to display the full content in editor window. As a comparison the right side preview window driven by markdown display instantly after changed event triggered