title: Material-UI OutlinedInput does not show the startAdornment
body: <p>Below are the codes. The start adornment does not appear in the textfield. Also, the label does not show any text.</p>
  <pre><code>&lt;InputLabel&gt;Mobile Number&lt;/InputLabel&gt;
              &lt;OutlinedInput
                variant=&quot;outlined&quot;
                autoComplete=&quot;outlined&quot;
                name=&quot;name&quot;
                required
                fullWidth
                label=&quot;Enter Mobile Number&quot;
                autoFocus
                inputProps={{
                  maxLength: 10,
                }}
                InputProps={{
                  startAdornment: (
                    &lt;InputAdornment position=&quot;start&quot;&gt;+1 &lt;/InputAdornment&gt;
                  ),
                }}
              /&gt;
  </code></pre>
  <p><a href="https://i.stack.imgur.com/MIKbj.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/MIKbj.png" alt="This is what it shows in the screen" /></a></p>