Ich denke mal, das ist das so genannte "Soft-Locking". Aus der Knowledgebase:
Document Locking:
In Notes/Domino 6.x, a database property feature called "Allow document locking" was introduced. When this property is enabled, any user with Author access or above can lock a document across all replicas. This prevents two or more users from making changes to the same document and then replicating - which would create replication conflict documents.
To enable this feature, you can select the database property "Allow document locking" in the basics tab.
Soft Locking:
Soft locking was also a new feature in Notes/Domino 6, but it was not documented as clearly as document locking. Soft locks are in-memory locks that are enabled when documents are in memory, and are not persistent. The editor takes out a soft lock on a document when it is opened in edit mode, and then unlocks it when the document is closed. During the period of time when it is soft locked, no one else can edit that document but it only affects the current replica where the user is working; it does not affect other replicas of the database.
Prior to release 6.5.1, soft locks could not be disabled. Beginning in releases 6.0.4, 6.5.1, and 7.0, users can add a NOTES.INI parameter EDIT_NO_SOFT_LOCKS=1 to their client's notes.ini.
The EDIT_NO_SOFT_LOCKS=1 ini parameter was added as a workaround for customers who had applications that did not work well with soft locking. The parameter essentially reverts locking behavior back to the R5 style, where soft locking did not exist. This parameter disables all soft locking in all databases accessed by that client. It cannot be enabled on a database by database basis.
At this time, there is no other way to disable soft locking. This parameter can be set programmatically in all clients via LotusScript with the following instructions:
Dim session As New NotesSession
Call session.SetEnvironmentVar( "EDIT_NO_SOFT_LOCKS", "1" , True)
The above script can be included in a Hotspot button included in a mail to all users.
An enhancement request, for soft locking be an option that can be enabled or disabled via a database property like document locking, has been submitted to Quality Engineering as SPR# JGON5WQLMA. There are no current plans to address this request.