The grids you see in Passwordstate are using ASP.NET controls from www.telerik.com. Obviously the sorting is not working now, as it's being treated as a text field. I did find this following article http://www.telerik.com/forums/sorting-the-grid-by-ipaddress, but I'm not sure how we could apply our own 'Custom Sorting' to a generic field, as how would we know it's intended to be used for storing IP Addresses.
In terms of performance, I did a test with a Password List which has 50 records stored in it, with all records displayed on the screen, and it took just under 2 seconds to sort - using Chrome as well, so I'm not exactly sure what the issue could be here. If you use Chrome's Developer tools, and click on the Network tab, is there anything obvious which is causing the delay?
I'm not sure if it helps, but when you search in a Password List, it also searches the text in generic fields - so maybe this would be a better option for you - depending on how you need to use the product I suppose.