ProtectFormatting Property [Excel 2003 VBA Language Reference]
True if chart formatting cannot be modified by the user. Read/write Boolean.
Remarks
When this property is True, the Object command on the Format menu is disabled and chart elements cannot be added, moved, resized, or deleted.
This property is not persisted when the file is saved. If you set this property to True and then reopen the file, it will no longer be set to True.
Example
This example protects the formatting of embedded chart one on worksheet one.
Worksheets(1).ChartObjects(1).Chart.ProtectFormatting = True
Applies to | Chart Object