iOS 6 Mobile Safari slow render of large table with select elements

[Patigell]

We're building a web application that has a page where the user sees a large table of editable items. This table has controls on each row to move the row up/down and the option to delete the row. Each row also has two select elements.This table could consist of around 200 rows in extreme circumstances, it is when we have lots of rows that we run into severe performance problems. The page is incredibly slow to scroll up and down and we see "checker-boxing" on the screen, also deleting a row takes around 30 seconds, sometimes more! Moving up and down takes a similar amount of time, and the page is generally unusable.We've been trying to narrow down exactly what the problem is and we're pretty sure it is to do with the select elements in the table - if we remove these from the rows; scrolling is perfect, moving up and down is ~1 second and deleting a row ~7 seconds. If we delete a row from the bottom of the 200 row table, it is near instant.It seems like the problem is to do with the CSS on the page, when we run the profiler it is the re-calculating of styles that is taking around 3 seconds.The page performs fine in other browsers, any help/knowledge would be great.Thanks