in, SmartClient_XXXXXXXX_LGPL, following 2 files,

isomorphic\skins\SmartClient\load_skin.js
isomorphic\skins\TreeFrog\load_skin.js

Code:
    ......
    if (isc.DateItem) {
        isc.DateItem.addProperties({
            pickerIconWidth:19,
            pickerIconHeight:16,
            pickerIconSrc:"[SKIN]/controls/date_control.png"
        })
    }
    ......
Icon miss-matched, should be:

pickerIconSrc:"[SKIN]/controls/date_control.gif"

Good to have someone to fix it.