extjs4.2 - how to override Extjs Timefield to show custom max value -

i want display 11:59 maxvalue extjs timefield increment=30. set maxvalue "23:59" did not work, , shows 23:30 maximum value. can specify function/code override display 11:59 maximum value?

thanks in advance.

try overriding 'createstore' function of 'ext.picker.time' include 23:59 in list, if maxvalue set 23:59 displayed.