Drag and drop record on list grid

SmartGWT : 4.1

Getting below error while drag and drop into another list grid
18:27:01.910 [ERROR] [smartgwtpoc] 18:27:01.881:MOU9:WARN:Log:InternalError: too much recursion
Stack from error.stack:
$wnd.isc.isA.String() @ :76
[a]MathFunction.Super() @ smartgwtpoc/sc/modules/ISC_Core.js:262
ListGrid._mightAcceptDrop() @ smartgwtpoc/sc/modules/ISC_Grids.js:2144
ListGrid.willAcceptDrop() @ smartgwtpoc/sc/modules/ISC_Grids.js:2144
[a]MathFunction.invokeSuper() @ smartgwtpoc/sc/modules/ISC_Core.js:270
[a]MathFunction.Super() @ smartgwtpoc/sc/modules/ISC_Core.js:262
ListGrid._mightAcceptDrop() @ smartgwtpoc/sc/modules/ISC_Grids.js:2144
ListGrid.willAcceptDrop() @ smartgwtpoc/sc/modules/ISC_Grids.js:2144
[a]MathFunction.invokeSuper() @ smartgwtpoc/sc/modules/ISC_Core.js:270