old_contents: import React from 'react'
  import { inject, observer } from 'mobx-react'
  import { grey } from 'material-ui/colors'
  import { dropTargetColor } from 'libs'
  import Tooltip from 'material-ui/Tooltip'
  import Sort from 'material-ui-icons/Sort'
  import IconButton from 'material-ui/IconButton'
  
  const borderBottom = `1px solid ${grey[200]}`
  const iconStyle = {
    width: '2rem',
    height: '2rem'
  }
  
  @inject('dragStore')
  @inject('arrangeStore')
  @observer
  export default class Title extends React.Component {
    onDragOver = (e) => {
      e.nativeEvent.preventDefault()
      const { win: { id }, dragStore: { setTargetWinId } } = this.props
      setTargetWinId(id)
    }
  
    onDrop = () => {
      this.props.dragStore.dropToNewWindow()
    }
  
    render () {
      const { win: { id, tabs }, dragStore: { targetWinId }, arrangeStore: { sortTabs } } = this.props
      const { length } = tabs
      const { onDragOver, onDrop } = this
      const style = {
        borderBottom,
        display: 'flex',
        paddingLeft: '2.5rem',
        paddingRight: 4,
        justifyContent: 'space-between',
        fontSize: '1.5rem',
        fontWeight: 'bold',
        lineHeight: '3rem'
      }
      const isOver = id === targetWinId
      const dropIndicator = isOver && (
        <span style={{
          flex: '1 1 auto',
          padding: '0 2rem'
        }}>
          drop here to create a new window
        </span>
      )
      if (isOver) {
        style.backgroundColor = dropTargetColor
      }
      return (
        <div style={style} {...{ onDragOver, onDrop }}>
          <span>
            {length} tab{length > 1 && 's'}
          </span>
          {dropIndicator}
          <Tooltip title='Sort Tabs'>
            <IconButton
              style={iconStyle}
              onClick={() => sortTabs(id)}>
              <Sort />
            </IconButton>
          </Tooltip>
        </div>
      )
    }
  }
  
new_contents: import React from 'react'
  import { inject, observer } from 'mobx-react'
  import { grey } from 'material-ui/colors'
  import { dropTargetColor } from 'libs'
  import Tooltip from 'material-ui/Tooltip'
  import Sort from 'material-ui-icons/Sort'
  import IconButton from 'material-ui/IconButton'
  
  const borderBottom = `1px solid ${grey[200]}`
  const iconStyle = {
    width: '2rem',
    height: '2rem'
  }
  
  @inject('dragStore')
  @inject('arrangeStore')
  @observer
  export default class Title extends React.Component {
    onDragOver = (e) => {
      e.nativeEvent.preventDefault()
      const { win: { id }, dragStore: { setTargetWinId } } = this.props
      setTargetWinId(id)
    }
  
    onDrop = () => {
      this.props.dragStore.dropToNewWindow()
    }
  
    render () {
      const { win: { id, tabs }, dragStore: { targetWinId }, arrangeStore: { sortTabs } } = this.props
      const { length } = tabs
      const { onDragOver, onDrop } = this
      const style = {
        borderBottom,
        display: 'flex',
        paddingLeft: '2.5rem',
        paddingRight: 4,
        justifyContent: 'space-between',
        fontSize: '1.5rem',
        fontWeight: 'bold',
        lineHeight: '3rem'
      }
      const isOver = id === targetWinId
      const dropIndicator = isOver && (
        <span style={{
          flex: '1 1 auto',
          padding: '0 2rem'
        }}>
          drop here to create a new window
        </span>
      )
      if (isOver) {
        style.backgroundColor = dropTargetColor
      }
      return (
        <div style={style} {...{ onDragOver, onDrop }}>
          <span>
            {length} tab{length > 1 && 's'}
          </span>
          {dropIndicator}
          <Tooltip title='Sort Tabs' placement='left'>
            <IconButton
              style={iconStyle}
              onClick={() => sortTabs(id)}>
              <Sort />
            </IconButton>
          </Tooltip>
        </div>
      )
    }
  }
  
subject: Change Tooltip placement to left