title: How to make focus stable for custom text field material-ui-pickers?
body: <p>When I passed custom text field to date picker then focus loses after each keyboard input. How to fix that?</p>
  
  <p>Sandbox example <a href="https://codesandbox.io/embed/datepicker-y0dn7" rel="nofollow noreferrer">https://codesandbox.io/embed/datepicker-y0dn7</a></p>
  
  <pre><code>  &lt;DatePicker
       keyboard
       label="Masked input"
       format="DD.MM.YYYY"
       mask={value =&gt;
         value
           ? [/\d/, /\d/, ".", /\d/, /\d/, ".", /\d/, /\d/, /\d/, /\d/]
           : []
       }
       value={selectedDate ? moment(selectedDate) : null}
       onChange={date =&gt; {
         handleDateChange(date);
         setFormattedValue(date.format("DD.MM.YYYY"));
       }}
       error={!!errorText}
       helperText={errorText}
       TextFieldComponent={props =&gt; (
         &lt;TextField
           {...props}
           value={formattedValue}
           onChange={event =&gt; setFormattedValue(event.target.value)}
         /&gt;
       )}
     /&gt;```
  </code></pre>