DevExpress Page Control Tab Click in Firefox

Our site uses DevExpress Page Controls (MVCxTabPage) and keyword tests which work fine in Chrome but only works some of the time in Firefox (never the same place twice). I see the click on the rendered tab and the focus changes to the tab but the page does not load. I've tried calling the focus operator before clicking and still it only works part of the time. I've noticed there is an 'Ambiguous recognition of the tested object" warning prior the error. This warning doesn't appear in Chrome or IE and I'm unable to find the Ambiguous object. Any thoughts what is happening???

@Html.DevExpress().PageControl( tab => {
	tab.Name = "partialProperties"; //!IMPORTANT: Do not rename, used by GridProperties view and javascript
	tab.CallbackRouteValues = new { Action = "_Properties" };

	/* Default & Required Settings */
	CribMaster.Web.Base.Util.Helper.ExtensionHelper.SetDefaultSettings(tab, ViewData["SelectTab"] == null ? TempData["ActiveTab"] : ViewData["SelectTab"]);
	/* End Default & Required Settings */

	/* ClientSideEvents Handlers */
	//!IMPORTANT: FIX tab reload on focusrowchanged bug
	tab.ClientSideEvents.BeginCallback = "OnBeginCallback"; //!IMPORTANT: required for GridProperties row change to work
	tab.ClientSideEvents.Init = "OnPropertiesInit";
	tab.ClientSideEvents.CallbackError = "HandleCallbackError";
	tab.ClientSideEvents.ActiveTabChanging = "OnPropertiesActiveTabChanging";
	//!IMPORTANT: Persist Model Primary Key between callback
	tab.ClientSideEvents.EndCallback = "OnPropertiesEndCallback";
	/* ClientSideEvents Handlers */

	tab.CustomJSProperties += (sender, e) => { e.Properties["cpModelKey"] = (Model == null ? string.Empty : Model.GetOriginalPrimaryKeyValue()); };

	STATION station;

	MVCxTabPage tabBinInfo = tab.TabPages.Add(MultiLanguageHelper.Localize("BinInformation"), "tabBinInfo");
	tabBinInfo.SetContent(() => {
		if (Model != null) {
			ViewContext.Writer.Write(Html.Hidden("IsNew", Model.IsNew)); //!IMPORTANT: for validation rules
			Html.RenderPartial("_PropertiesBinInformation");
		}
	});