little issue with filtering

Hi,

I found a little issue in the filtering.
If you move the cursor after begining to type, filtering don't work
Example : http://datatables.net/examples/example_zero_config.html
type "win" in the search field. It work well.
click with the mouse juste before the "w" in the search field
type "gecko " (then now in the search field you have "gecko win")
Filtering don't work, found 0 result (instead of 17)
type another space, and the push the BACKSPACE key, then filtering work good

It's not really important, i do not need you fix them, just report it ;-)

Thank you for your great work ! (and for the greatest 1.5 :D )