CodeMirror有内容，但直到按下按键后才会显示

I have a CodeMirror instance embedded in a webapp I'm building. It works great - except that the initial content won't display until user enters a new character. So it is all there but hidden until the user forces a change. This is bad. Is there any way I can force a repaint or refresh of the browser of simulate a character enter - whitespace will do.I have a CodeMirror instance embedded in a weba