Small CSS issues in date/date_popup/themes/timeentry and datepicker.css

While debugging another issue, I found some small points and hopefully the fix for the first one.

I don't fully understand this, but after a Google I found that if I change:

.timeEntry {
background-color: none !important;

to

.timeEntry {
background-color: transparent;

... I stop getting an error reported in firebug. 'none' wasn't an option in the CSS tutorial I looked at.

I also get:

"Error in parsing value for property 'filter'. Declaration dropped.
http://example.com/subdir/sites/all/modules/date/date_popup/themes/datep...
Line 177

.ui-datepicker-cover {
.. snip ..
filter: mask(); /*must have*/ <== line 177

... but when I looked this up there were references to things that are not yet standards and it's in an IE fix block, so that's beyond my understanding at the moment.

This second error also occurs (in Firefox) for

nice_menus/nice_menus.css?x
Line 122

flag/theme/flag.css?x
Line 21

I feel like I'm being pickey! ... but I suppose every little helps.