default value disappeared the custom field default configuration

Issue Summary

The default value disappeared in the Custom field default configuration when trying to add a new project to the Default configuration scheme. 

Steps to Reproduce

1. Create a Custom Field type "Message Custom Field (for Edit)"
2. Configure the newly created custom field and try to edit the Default Value 
3. Configure again the custom field  by adding another Project to the scope 
4. Try to Edit again the old default value

Expected Results

When trying to edit the default value after adding another project to the scope, the old default value shouldn't disappear. 

Actual Results

When trying to edit the default value after adding another project to the scope, the old default value disappeared. 

Observation: Not able to find the default value in the database customfieldvalue table (before/after editing) 

Workaround

No workaround