<p>The problem is <a href="https://github.com/openstreetmap/openstreetmap-website/blob/master/app/assets/stylesheets/common.css.scss#L1537">https://github.com/openstreetmap/openstreetmap-website/blob/master/app/assets/stylesheets/common.css.scss#L1537</a> which sets the height of text areas to 100% with the <code>!important</code> flag, so it overrides the dynamically determined height which the auto grow plugin sets.</p>

<p>That line came in with <a href="https://github.com/openstreetmap/openstreetmap-website/commit/c3b8897c44531788f06a51e24470e97a3abfb7b8" class="commit-link"><tt>c3b8897</tt></a>.</p>

<p style="font-size:small;-webkit-text-size-adjust:none;color:#666;">—<br>Reply to this email directly or <a href='https://github.com/openstreetmap/openstreetmap-website/issues/330#issuecomment-20878498'>view it on GitHub</a>.<img src='https://github.com/notifications/beacon/uTRSc6ihLa7Shf84BpiOpu4cjV7SYEEC0K8ln00e-rj73o0JwNIg1yaI2TExh5re.gif' height='1' width='1'></p>