Adding categorisation to custom module after it has already

When you add a categorisation property to an existing custom module, when you go to edit and existing item or add a new one it breaks.

If you add the classification at the time of creation (before activating) it is fine.

Steps to reproduce (Latest version):

- Create custom module
- Activate it
- Add classification property and save changes
- try and create a module item 

Server Error in '/' Application.Object reference not set to an instance of an object.Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error: 

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace: 

[NullReferenceException: Object reference not set to an instance of an object.]
Telerik.Sitefinity.TaxonomyPropertyDescriptor.GetValue(Object component) +240
Telerik.Sitefinity.Data.WcfHelpers.DynamicFieldsDataContractSurrogate.GetObjectToSerialize(Object obj, Type targetType) +331
Telerik.Sitefinity.DynamicModules.DynamicModuleManager.GetBlankItem(Type contentType) +86
Telerik.Sitefinity.Web.UI.ContentUI.Views.Backend.Detail.DetailFormView.CreateBlankDataItem() +161
Telerik.Sitefinity.Web.UI.ContentUI.Views.Backend.Detail.DetailFormView.GetScriptDescriptors() +266
Telerik.Sitefinity.DynamicModules.Web.UI.Backend.DynamicContentDetailFormView.GetScriptDescriptors() +10
System.Web.UI.ScriptControlManager.RegisterScriptDescriptors(IScriptControl scriptControl) +175
Telerik.Sitefinity.Web.UI.ContentUI.Views.Backend.ViewBase.Render(HtmlTextWriter writer) +145
System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +149
System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +248
System.Web.UI.WebControls.WebControl.RenderContents(HtmlTextWriter writer) +14
System.Web.UI.WebControls.WebControl.Render(HtmlTextWriter writer) +51
System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +149
System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +248
System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +149
System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +248
System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +149
System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +248
System.Web.UI.WebControls.WebControl.RenderContents(HtmlTextWriter writer) +14
System.Web.UI.WebControls.WebControl.Render(HtmlTextWriter writer) +51
System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +149
System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +248
System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +149
System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +248
System.Web.UI.HtmlControls.HtmlForm.RenderChildren(HtmlTextWriter writer) +394
System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer) +48
System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +149
System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +248
System.Web.UI.Page.Render(HtmlTextWriter writer) +39
System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +149
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +5362

Hello Roberto,

I was not able to recreate the behavior you describe on a clear 7.0 project. Here is a video of the behavior on my machine. Feel free to correct my steps if necessary.

If you are experiencing this behavior on your end, feel free to send us a support ticket where we can investigate this in further depth on your particular solution.

Regards,
Ivan D. Dimitrov
Telerik