Assuming that both users cannot work in collaboration at the same time on the same form:

Case I: User 1 is editing the form ABC
- On the forms list, User 2 gets an indication that form ABC is in edit mode right now.
- If User 2 opens form ABC, it will open in read-only mode. He cannot make any changes.
- User 2 can only see the updated version when he closes and opens the new version of the form again.

Case II: User 1 has deleted/moved form ABC
- User 2 just opens the form ABC, and he gets a notification at the same time that the action cannot be completed as the selected item has already deleted/moved.

Need to notify users that the form has recently been edited?
I am stumped so I hope I can present my question in a manner that allows me to get some support. I am creating a Lead validation rule  that in essence is 3 tiers i.e. if tier 1 is selected require that tier 2 is selected and if this value in tier 2 is selected require  tier 3 text to be completed. Here are my picklist requirements

Lead Source           Lead Source Details                       Complete Text Field

Wholesaler
                          &gt;ABC Wholesaler
                          &gt;XYZ Wholesaler
                          &gt;Other if other is selected complete   [text field]   

Personal Referral
                         nothing else here

Trade Show/Event
                         nothing else here but we need to &gt;   [text field]

TBP Event
                         nothing else here but we need to &gt;   [text field]

Website
                         nothing else here

Other
                          nothing else here but we need to &gt;   [text field]


When this was only a 2 tier picklist I used this validation rule but now I can't figure out how to rewrite for 3 tier

ISBLANK(Lead_Source_Details__c)
&amp;&amp;
(
    ISPICKVAL(LeadSource, "Distribution Partner")
    || ISPICKVAL(LeadSource, "Event/Trade Show")
    || ISPICKVAL(LeadSource, "TBP Event")
    || ISPICKVAL(LeadSource, "Other")
)
