GLObject/DisplayOpts instances call their base class destroy method,

and/or clear all refs. The order of execution in destroy methods is
important.

fsl/fslview/displaycontext/modelopts.py

@@ -62,12 +62,14 @@ class ModelOpts(fsldisplay.DisplayOpts):
 
 
     def destroy(self):
-        fsldisplay.DisplayOpts.destroy(self)
         self.overlayList.removeListener('overlays', self.name)
 
         for overlay in self.overlayList:
             overlay.removeListener('name', self.name)
 
+        fsldisplay.DisplayOpts.destroy(self)
+
+
 
     def getReferenceImage(self):
         """Overrides :meth:`.DisplayOpts.getReferenceIamge`.

fsl/fslview/displaycontext/vectoropts.py

@@ -71,12 +71,13 @@ class VectorOpts(volumeopts.ImageOpts):
 
 
     def destroy(self):
-        volumeopts.ImageOpts.destroy(self)
         self.overlayList.removeListener('overlays', self.name)
 
         for overlay in self.overlayList:
             overlay.removeListener('name', self.name)
 
+        volumeopts.ImageOpts.destroy(self)
+
         
     def __overlayListChanged(self, *a):
         """Called when the overlay list changes. Updates the ``modulate``

fsl/fslview/gl/gllabel.py

@@ -39,6 +39,7 @@ class GLLabel(globject.GLImageObject):
 
         self.removeListeners()
         fslgl.gllabel_funcs.destroy(self)
+        globject.GLImageObject.destroy(self)
 
 
     def addListeners(self):

fsl/fslview/gl/gllinevector.py

@@ -205,10 +205,10 @@ class GLLineVector(glvector.GLVector):
 
         
     def destroy(self):
-        glvector.GLVector.destroy(self)
-        fslgl.gllinevector_funcs.destroy(self)
         
         self.displayOpts.removeListener('lineWidth', self.name)
+        fslgl.gllinevector_funcs.destroy(self)
+        glvector.GLVector.destroy(self)
 
 
     def getDataResolution(self, xax, yax):

fsl/fslview/gl/glmodel.py

@@ -42,6 +42,10 @@ class GLModel(globject.GLObject):
         self._renderTexture.destroy()
         fslgl.glmodel_funcs.destroy(self)
         self.removeListeners()
+        
+        self.overlay = None
+        self.display = None
+        self.opts    = None
 
         
     def addListeners(self):

fsl/fslview/gl/glvector.py

@@ -115,6 +115,8 @@ class GLVector(globject.GLImageObject):
 
         self.removeListeners()
 
+        globject.GLImageObject.destroy(self)
+
 
     def addListeners(self):