If I remove batch editing mode, values in DropDownList can be changed with no problem.
I have tested the page you have attached (Telerik controls version: 2014.2.724.45) and I reproduce the issue with IE10. I can send you a video but it cannot be attached. Dropdown value cannot be changed. It only changes if you move the cursor in the grid.
In Chrome is working fine.
Thanks for your help,
answered on 30 Sep 2014, 09:04 AM
A week after my previous post we were able to replicate the issue you are describing and we have located what is causing it. Indeed, the problem was in some internal logic in Batch Editing, which was causing issues with external controls.
Nevertheless, I am pleased to inform you that a fix for this will be introduced in our upcoming release.
For the time being, you can use the following workaround:
Telerik.Web.UI.GridBatchEditing.prototype._mouseDown = function (e)