Symptoms
The following error appears from time to time on SmartForms runtime affecting all users:
Extender control '%SOME_GUID%' is not a registered extender control. Extender controls must be registered using RegisterExtenderControl() before calling RegisterScriptDescriptors(). Parameter name:extenderControl
Performing recycle operation for SmartForms application pool resolves this. How to properly isolate root cause of this issue?
Diagnoses
Such exception always points to the table control GUID (table control is just a table layout which you create on forms/views to place other controls inside of it) and is actually caused by another control inside of the the table.
The original error is lost and replaced with the table control generic error since the rendering continues and the table was not correctly added due to the underlying error. However if error logging is enabled and the folder "C:debug" is present with write permissions for authenticated users then we can see the underlying error.
To investigate this properly we need to enable this additional logging and run with it until issue will reoccur again. We need the additional log information to diagnose why the issue occurred and cannot proceed with investigations without it. Settings to enable logging in web.config:
<add key="Forms.Global.ErrorLogging.Enabled" value="true" />
<add key="Forms.Global.Logging.Enabled" value="true" />
<add key="Forms.Global.ErrorLogging.FilePath" value="C:DebugSourceCode.Forms.Web.error" />
When dealing with this error it may also be useful to audit any custom controls you are using in your environment to make sure they all compatible with K2 version you are use and install updated version if applicable or remove incompatible one.
Resolution
Enable forms logging as described above and troubleshot based on error message obtained from these logs.
Audit any custom controls you are using in your environment to make sure they all compatible with K2 version you are use and install updated version if applicable or remove incompatible one.
