diff --git a/GPy/core/parameterization/parameter_core.py b/GPy/core/parameterization/parameter_core.py
index 6be83db2..2096c55a 100644
--- a/GPy/core/parameterization/parameter_core.py
+++ b/GPy/core/parameterization/parameter_core.py
@@ -515,19 +515,12 @@ class Indexable(Nameable, Observable):
     #===========================================================================
     # Tie parameters together
     #===========================================================================
-    
-    def _has_ties(self):
-        if self._highest_parent_.ties.tied_param is None:
-            return False
-        if self.has_parent():
-            return self._highest_parent_.ties.label_buf[self._highest_parent_._raveled_index_for(self)].sum()>0
-        return True
-    
+        
     def tie_together(self, *plist):
         plist = list(plist)
         plist.append(self)
         self._highest_parent_.ties.tie_together(plist)
-        self._highest_parent_._set_fixed(self,self._raveled_index())
+#         self._highest_parent_._set_fixed(self,self._raveled_index())
         self._trigger_params_changed()
 
     #===========================================================================
@@ -683,9 +676,10 @@ class OptimizationHandlable(Indexable):
             if self.has_parent() and (self.constraints[__fixed__].size != 0 or self._has_ties()):
                 fixes = np.ones(self.size).astype(bool)
                 fixes[self.constraints[__fixed__]] = FIXED
-                return self._optimizer_copy_[np.logical_and(fixes, self._highest_parent_.ties.getTieFlag(self))]
+                fixes[self._highest_parent_.ties.label_buf[self._highest_parent_._raveled_index_for(self)]] = FIXED
+                return self._optimizer_copy_[fixes]
             elif self._has_fixes():
-                    return self._optimizer_copy_[self._fixes_]
+                    return self._optimizer_copy_[np.logical_and(self._fixes_,self.ties.label_buf==0)]
 
             self._optimizer_copy_transformed = True
 
diff --git a/GPy/core/parameterization/ties_and_remappings.py b/GPy/core/parameterization/ties_and_remappings.py
index 2c1984d9..f567fab2 100644
--- a/GPy/core/parameterization/ties_and_remappings.py
+++ b/GPy/core/parameterization/ties_and_remappings.py
@@ -55,7 +55,7 @@ class Tie(Parameterized):
     TODO:
     1. Add the support for multiple parameter tie_together and tie_vector
     2. Properly handling parameters with constraints
-    3. Properly handling the merging of two models
+    3. Properly handling the merging of two models [DONE]
     4. Properly handling initialization
     
     """
@@ -64,7 +64,6 @@ class Tie(Parameterized):
         # If ture, it does not need to check consistency
         self._PROPAGATE_VAL_ = False
         super(Tie, self).__init__(name)
-        self.size = sum(p.size for p in self.parameters)
         self.tied_param = None
         # The buffer keeps track of tie status
         self.label_buf = None
@@ -146,7 +145,6 @@ class Tie(Parameterized):
             self.tied_param.tie[:old_size] = old_tie_
             self.tied_param.tie[old_size:] = range(start_label,start_label+num)
         self.add_parameter(self.tied_param)
-        self.size = sum(p.size for p in self.parameters)
         return range(start_label,start_label+num)
 
     def _remove_tie_param(self, labels):
@@ -163,7 +161,6 @@ class Tie(Parameterized):
             self.tied_param = Param('tied',new_buf)
             self.tied_param.tie[:] = old_tie_[idx]
             self.add_parameter(self.tied_param)
-        self.size = sum(p.size for p in self.parameters)
     
     def _merge_tie_labels(self, labels):
         """Merge all the labels in the list to the first one"""
@@ -177,7 +174,7 @@ class Tie(Parameterized):
             self.label_buf = None
             self.buf_idx = None
         else:
-            self.label_buf = np.zeros((self._highest_parent_.size,),dtype=np.uint32)
+            self.label_buf = np.zeros((self._highest_parent_.param_array.size,),dtype=np.uint32)
             self._traverse_param(lambda x:np.put(self.label_buf,self._highest_parent_._raveled_index_for(x),x.tie), self._highest_parent_, [])
             self.buf_idx = self._highest_parent_._raveled_index_for(self.tied_param)
         
diff --git a/GPy/kern/_src/psi_comp/__init__.py b/GPy/kern/_src/psi_comp/__init__.py
index 7a5851fb..c421afd8 100644
--- a/GPy/kern/_src/psi_comp/__init__.py
+++ b/GPy/kern/_src/psi_comp/__init__.py
@@ -28,6 +28,9 @@ class PSICOMP_RBF(Pickleable):
             return ssrbf_psi_comp.psiDerivativecomputations(dL_dpsi0, dL_dpsi1, dL_dpsi2, variance, lengthscale, Z, variational_posterior)
         else:
             raise ValueError, "unknown distriubtion received for psi-statistics"
+
+    def _setup_observers(self):
+        pass
         
 class PSICOMP_Linear(Pickleable):