Filter pannel hidden if table is too short

[shershen08]

Here's how it looks (latest Chrome@MacOS) :

Should be fixable by CSS overflow:hidden property change of the main table.
I could make PR if you will

[LucienLee]

Oh, the overflow: hidden is used to cut the first bloating group date column.
Instead of exploiting rowspan to make grouping cell, I made forged cell with span and set height as the amount of date grouping. The reason is layout would recalculating and cause jerky animation if the first row of the date grouping be filtered.

For example, the date column of second row make the following date columns. When first one row be filtered, the second one has to be replaced the original first one. In that moment, the table would be relayout.

Date	Content
March 2014(rowspan="3")	1...
(null)	2...
(null)	3...

You can pull the rowspan br to see what happened.

Anyway, I would fix that and thanks for your report.