Calendar Selected Date Missing Box

This is one of the most annoying things in piwik. When I click on a date, the back-box around the date goes away, or if I hover over the date, then the box is gone. It confuses people because they expect the date they click on to be highlighted, not to go blank. I found this code in _popups.less that I think is causing the issue from the background: none !important line.
.ui-state-default, .ui-widget-content .ui-state-default, .ui-widget-header .ui-state-default {
border: 0px !important;
.ui-icon {
&:hover {
background: none !important;

[attachment 2070 2015-01-05_13-14-19.png]

Hi Sphere, can you please post this in github issue tracker Issues · matomo-org/piwik · GitHub ? we’ll investigate