Editing 'Change basic information' of any CCK field erase Form Markup values

Issue Summary

Editing 'Change basic information' of any CCK field erase Form Markup values

Step to reproduce this issue
Create a new CCK content type at admin/content/types/add

Add a text field at admin/content/node-type/YOUR-CONTENT-TYPE-NAME-HERE/fields

Add a Form Markup prefix to this field at admin/content/node-type/YOUR-CONTENT-TYPE-NAME-HERE/fields/field_YOUR-FIELD-NAME-HERE

Click on SAVE FIELD SETTINGS button.

Edit the text field at admin/content/node-type/YOUR-CONTENT-TYPE-NAME-HERE/fields/field_YOUR-FIELD-NAME-HERE

Under the section 'basic information' click on CHANGE BASIC INFORMATION button. Find attached screenshot to clarify. Edit the LABEL.

Click on CONTINUE button.

On the next page notice that the Form Markup prefix has been deleted. Expected result is to not delete the Form Markup prefix.

With:
-CCK 6.x-2.5
-Form Markup 6.x-1.1