[imp] refresh button not work in smartphone mode

[Nethub Online]

Hi all,

the refresh button is not working on smartphone mode, tested platforms on
ipad ios 5, iphone ios 5 & 6, firefox 13 & 22

On FF error console, it shows:

Timestamp: 13/7/2013 0:08:39
Error: TypeError: ob is undefined
Source File:
http://webmail.test.com/imp/js/smartmobile.js?v=5e98e6c9c4aa9cc91ffb4a1defbcb044
Line: 502

The line is relating to:
            cid = ImpMobile.mailbox + '|' + ob.cacheid + '|' + ob.slice;


Horde Version: 5.1.1
Imp [Mail]: H5 (6.1.2)
PHP Version: 5.3.3

Hope this can be fixed in future version

Ming