diff --git a/beat/web/plotters/models.py b/beat/web/plotters/models.py
index 03da7c3964bc78d9878b7ddeb20b675ca7877733..0396001a23124e48338d483f7b11c6806fed7d6e 100755
--- a/beat/web/plotters/models.py
+++ b/beat/web/plotters/models.py
@@ -50,6 +50,7 @@ from ..common.models import get_contribution_description_filename
 from ..code.models import Code
 from ..code.models import CodeManager
 from ..code.models import get_contribution_source_code_filename
+from ..common.models import Shareable
 
 import simplejson
 import collections
@@ -275,6 +276,15 @@ class PlotterParameter(Contribution):
     description       = models.TextField(default='', blank=True, null=True, help_text=Messages['description'])
     plotter           = models.ForeignKey(Plotter, related_name='plotting_parameters', null=True)
 
+    #_____ Methods __________
+
+    def modifiable(self):
+        """Can be modified if nobody points at me"""
+        return super(PlotterParameter, self).modifiable() and (self.defaults.count() == 0)
+
+    def deletable(self):
+        """Can be deleted if nobody points at me"""
+        return super(PlotterParameter, self).deletable() and (self.defaults.count() == 0) and (self.sharing == Shareable.PRIVATE)
 
     #_____ Utilities __________