cannot add widget to RTC dashboard

could you please expand on this, of interest would be the specific
-  widget
-  version of RTC
-  were the project categories in RTC altered in any way

if it is the CQ Widget, here is one earlier issue that I would like to mention:
     ClearQuest Widget not found when selecting CQ Application in Dashboard (177083)
which was resolved after a reboot of the CQ server and re applying of the association to cq schema repo in RTC.

I do not know of any known issue for this
but I suspect the storage area keys may need to be verified. 

If storage area keys stored in the DB for
      Dashboard (com.ibm.team.dashboard, com.ibm.team.dashboard.nohistory, net.jazz.ajax.theme)
differ from the keys referred to by
      JTS in the Web UI
you might experience Dashboard issues. 

to verify:
1.  Check Consumers (Inbound) for "com.ibm.team.dashboard" from
     https://repo_url:403/jts/admin#action=com.ibm.team.repository.admin.configureOAuth
2.  Check for the same key in DB using
     repotools-jts -listStorageAreaKeys toFile="jts_keys.log"
     if they do not match,
     -  alter the value against "com.ibm.team.dashboard" in "jts_keys.log" and perform a
     -  set the same value for "com.ibm.team.dashboard.nohistory" as well
and perform
     repotools -setStorageAreaKyes fromFile="jts_keys.log"
    
you may additionally need to check the match for "net.jazz.ajax.theme" as well.

if this does not still help, I would suggest contacting Support.