This is a wish: would it be worthwhile to add the ability to show ajax processing? For example, I have extra code that reduces the opacity of the table rows whenever ajax is processing rows due to filterStart, sortStart or pageMoved:
$('table tr td').css('opacity', 0.25);
Upon ajaxComplete, then the opacity is set back to 1. Such formatting could be hardcoded to occur if the appropriate option is select or somehow give admins the ability to customize the formatting effect desired.
Also, If only one header is being targeted (sorting or filtering), then only that header will show an indicator. And that can be modified by css (here is the blue theme specific code).
I guess I could also add a class name to the table so you can apply whatever other styling you desire.
If you want to use scripting, then you can bind to the sortBegin and sortEnd events and do whatever, or just replace the $.tablesorter.isProcessing function.
That did it! Another block of code I can get rid of - thanks so much!