Trade failed, cannot reopen trade

[Malong]

I don't know if this is consistently reproducible, but here are the circumstances:

* 11112 sends trade request to 2516978
* 2516978 opens trade, adds items, clicks accept
* 11112 adds item, clicks accept
** checkbox for 2616978 gets unchecked
* 2516978 clicks accept
* nothing gets traded, all items are still in respective characters' inventories
* 11112 sends trade request to 2516978
** Message displays "You already have a trade open with that character!"
** No trades are displayed under Active Trades