I don't manage to reproduce this one consistently or even easily, but for sure sometimes the control, are being partially hidden, as if the overflow was hidden.
It ends up looking like this, making the datatable controls unusable / un-reachable:
Here is how to reproduce consistently:
Looks like a limitation of HTML/CSS as per http://stackoverflow.com/a/6112856
Solution could be to extract the DOM node for the footer list, and move it out of the container.. likely we don't do it (non trivial?)
very non trivial
Moving back to 3.0.0 (ie. we don't need to do it before release, maybe during 3.X dev cycle...)