LPS-40665 - Mobile dockbar icons behave inconsistently

Hey @brunobasto,

Attached is an update for http://issues.liferay.com/browse/LPS-40665.  I sent you this pull to review since I reverted a CSS fix that you added in https://github.com/liferay/liferay-portal/blame/master/portal-web/docroot/html/themes/_styled/css/dockbar.css#L504.  I just wanted to make sure I did not break anything with your change, so can you take a look and if it is good, can you send it to @natecavanaugh?

Please let me know if you have any questions.  Thanks!