Context menu error

v9.05.606

I have a customized customer entry form. Some users get an error when they open it using right-click on customerId: Open with: Customer Entry, but not all users. They don't get an error if they open it from the menu.

Just to save you the obvious:
1) I saved the customization as CUST_1
2) I put CUST_1 in the menu as UDCUST
3) I changed the context menu to point to UDCUST
4) I cleared the user's cache
5) I removed personalizations

Epicor wasn't much help blaming it on my customization. But it doesn't make sense since they can open the customized screen fine from the menu - only from right-click do they get the error.

Thanks in advance if anybody can lead me in the right direction here.

Randy