bootstrap 4, height of input vs select are different
<p>Can someone show why this happens</p>

<pre><code>&lt;div class="row"&gt;
    &lt;div class="col-xs-6"&gt;
        &lt;div class="form-group"&gt;
            &lt;input type="text" class="form-control form-control-sm" /&gt;
        &lt;/div&gt;
    &lt;/div&gt;
    &lt;div class="col-xs-6"&gt;
        &lt;div class="form-group"&gt;
            &lt;select class="form-control form-control-sm"&gt;
                &lt;option&gt;select&lt;/option&gt;
            &lt;/select&gt;
        &lt;/div&gt;
    &lt;/div&gt;
&lt;/div&gt;
</code></pre>

<p>When it renders on any browser, bootstrap 4. the height of the input is 3 pixels more than a select.
thanks</p>