When we do a mass modification (as admin of the tracker) using the masschange button, the "Permissions on artifact" field has to be Completed but we would like to keep the initial value.

Reproduction process:

• Create a "Permissions on artifact" field with the option "Required" enabled.
• Create 2 artefacts with "Permissions on artifact" field completed.
• Select at least this 2 artifacts in mass modification with the masschange button.
• Make a change that does not concern the Permission field There is an error message saying to enter a value for the Permissions field