WB22 table on a tablet / ipad

Hey

I have a website made in wd22. On a page there is a table. This table is:
- Ajax table
- Unlimited rows / all in browser cache
- content by programming
- about 500 rows

when i select a row on a tablet i takes 5 a 6 seconds to show the selection bar
when i select a row on a iPad i takes 2 a 3 seconds to show the selection bar

there is noting in the display event of the table.
Why does this take so long??


TIA
Jan