Displaying 'null' values

I’ve noticed that any time we pass in a null value for data, it displays it as a space which with tooltips is very ugly. Is there a way to adjust this behavior to automatically turn off the tooltips for that cell (have no space or title attribute created)?

Unfortunately it’s not available to disable ‘null’-tooltips in IE for the reason of native behaviour of the browser.
In other broser empty tooltip should not pop-up.