Button single click becomes disabled permanently if a validation error is detected. After satisfying the validator conditions the button doesn't get enabled and it is not possible to post back the page.
The issue is resolved and the fix will be available in the next Service Pack Q2 2014 SP1 scheduled for mid of July as well in the next internal build.
As a workaround you can use the following JavaScript overwrite: var oldSingleClickedFunction = Telerik.Web.UI.Button.SingleClickFunctionality.prototype.clicked; Telerik.Web.UI.Button.SingleClickFunctionality.prototype.clicked = function (args) { if (this.options.controlState.validationResult) return oldSingleClickedFunction.call(this, args); else return this.base.clicked(args); }