title: Why does Material UI's "withStyles" not allow camelCase props?
body: <p>While working with the new Material UI (version 1.0.0-beta.33 as of this post), I'm having a lot of trouble with prop casing. It seems as if <code>withStyles</code> arbitrarily allows camelCased props in some cases and not in others.</p>
  
  <p>For example:</p>
  
  <pre><code>&lt;ChipInput
      dataSource={defaultGroups}
      defaultValue={this.state.groups}
      fullWidth={true}
      label="Test Groups"
      newChipKeyCodes={[9, 13, 32, 186, 188]}
      onChange={chips =&gt; this.submitForm(field, this.state.groups, chips.toString())}
      openOnFocus={true}
  /&gt;
  </code></pre>
  
  <p>I've seen this repeatedly while working with the latest Material UI. In this case I'm using a prop called <code>openOnFocus</code> with the <code>Material-ui-chip-input</code> library (version 1.0.0-beta.3) and I'm getting this error in the console:</p>
  
  <pre><code>Warning: React does not recognize the `openOnFocus` prop on a DOM element. 
  If you intentionally want it to appear in the DOM as a custom attribute, 
  spell it as lowercase `openonfocus` instead. If you accidentally passed it 
  from a parent component, remove it from the DOM element.
  in div (created by Input)
  in Input (created by WithStyles(Input))
  in WithStyles(Input) (created by ChipInput)
  in div (created by ChipInput)
  in div (created by FormControl)
  in FormControl (created by WithStyles(FormControl))
  in WithStyles(FormControl) (created by ChipInput)
  in ChipInput (created by WithStyles(ChipInput))
  in WithStyles(ChipInput)
  in div
  in Unknown (created by ConnectedField)
  in ConnectedField (created by Connect(ConnectedField))
  in Connect(ConnectedField) (created by Field)
  in Field (created by TestMethodDetails)
  in div (created by TestMethodDetails)
  in div (created by TestMethodDetails)
  in div (created by TestMethodDetails)
  in form (created by TestMethodDetails)
  in div (created by TestMethodDetails)
  in TestMethodDetails (created by Form(TestMethodDetails))
  in Form(TestMethodDetails) (created by Connect(Form(TestMethodDetails)))
  in Connect(Form(TestMethodDetails)) (created by ReduxForm)
  in ReduxForm (created by Connect(ReduxForm))
  in Connect(ReduxForm) (created by ProjectTestMethodView)
  in div (created by ProjectTestMethodView)
  in ProjectTestMethodView (created by Connect(ProjectTestMethodView))
  in Connect(ProjectTestMethodView) (created by Route)
  in Route (created by ProjectView)
  in div (created by ProjectView)
  in div (created by ProjectView)
  in ProjectView (created by Connect(ProjectView))
  in Connect(ProjectView) (created by Route)
  in Route (created by App)
  in Switch (created by App)
  in div (created by App)
  in section (created by Content)
  in Content (created by Connect(Content))
  in Connect(Content) (created by Layout)
  in div (created by Layout)
  in Layout (created by App)
  in div (created by App)
  in MuiThemeProvider (created by App)
  in App (created by Connect(App))
  in Connect(App) (created by Route)
  in Route (created by withRouter(Connect(App)))
  in withRouter(Connect(App))
  in Router (created by ConnectedRouter)
  in ConnectedRouter
  in AppContainer
  in Provider
  </code></pre>
  
  <p>Why am I not able to use <code>openOnFocus</code> with Material UI themes, but it doesn't complain about other props like <code>fullWidth</code>? I can use camelCase props on normal react components just fine.</p>