Hyperlink on Custom entity record is not working after Upgrade to v7.3

Hi,

After the upgrade to version 7.3 I have found the following issue.

I have a Contract field on the Opportunity screen, and as there is no standard solution for hyperlinking the value of this field to the Contract record we have set up the workaround solution which was changing the title of the field to a hyperlink instead using the followin JS on the CreateScript value of the field :

var intRecordId = CRM.GetContextInfo("opportunity","oppo_contractsid");
if (intRecordId != '')
{
var strURL = CRM.URL("contracts/contractssummary.asp")+"&cont_contractsid="+intRecordId;
var strCaptionText = "Contract";
var strFullCaption = "<a href="+strURL+">"+strCaptionText+"</a>:";
Caption = strFullCaption;
}

Problem is it's not working anymore and it gives now an error message (given in french which I've translated) :

"Incorrect page management parameters. CurrentEntity param (MC_currententity) empty.

Verify the page with the entry point PARAM=undefined"

I presume I am missing some new params or that the syntax has changed on 7.3. but I don't know what to add in my JS code...

Does anybody know what to do here ?

Thanks for your help !

Proconsult