Failure when writing HTML in preview editor

[fxha]

Description

An exception occurs when writing HTML tags and pressing enter to autocomplete the tag.

Steps to reproduce

1. Write some HTML like <div> and press Enter

Stack Trace:

TypeError: Cannot read property 'text' of null
    at ContentState.checkNeedRender (webpack-internal:///./src/muya/lib/contentState/updateCtrl.js:52:95)
    at ContentState.clickHandler (webpack-internal:///./src/muya/lib/contentState/clickCtrl.js:211:35)
    at HTMLDivElement.handler (webpack-internal:///./src/muya/lib/eventHandler/clickEvent.js:204:20)

TypeError: Cannot read property 'type' of null
    at eval (webpack-internal:///./src/muya/lib/contentState/paragraphCtrl.js:36:153)
    at Array.filter (<anonymous>)
    at ContentState.selectionChange (webpack-internal:///./src/muya/lib/contentState/paragraphCtrl.js:36:74)
    at Muya.eval (webpack-internal:///./src/muya/lib/index.js:61:50)
    at eval (webpack-internal:///./src/muya/lib/eventHandler/keyboard.js:102:19)

Versions

• Mark Text: develop
• Operating system: all