Hi Steve,
Thank you for your purchase.

Can you please send me some example and tell me what do you want to achieve so I can give you my suggestion.

Thank you.

HI Steve,

We had that option in our previous releases but It caused many issues with the themes so we need to remove it.

There is some workaround that is suggested by our user but we did not have time to test it out. 
Here is that java script so maybe it can help you.

var table = document.querySelector('table');
if (table != null )    
window.addEventListener('scroll', function(){
var top = table.getBoundingClientRect().top;
top = document.body.className.search('admin') > 0 ? top - 32 : top;
if (top < 0 )
table.querySelector('thead').style.transform = 'translateY( '+ (-top) +'px )'; else
table.querySelector('thead').style.transform = 'translateY( 0px )';      
table.querySelector('thead').style.background = '#fff';
});

Best regards.