diff --git a/wx/lib/agw/pycollapsiblepane.py b/wx/lib/agw/pycollapsiblepane.py
index 26437ec8..41a441fe 100644
--- a/wx/lib/agw/pycollapsiblepane.py
+++ b/wx/lib/agw/pycollapsiblepane.py
@@ -481,8 +481,6 @@ class PyCollapsiblePane(wx.Panel):
         :param `sz`: an instance of :class:`Size`.
         """
 
-        # minimal size has priority over the best size so set here our min size
-        self.SetMinSize(sz)
         self.SetSize(sz)
 
         if self.HasAGWFlag(wx.CP_NO_TLW_RESIZE):
@@ -534,7 +532,7 @@ class PyCollapsiblePane(wx.Panel):
                     # collapsed . expanded transition
 
                     # force our parent to "fit", i.e. expand so that it can honour
-                    # our minimal size
+                    # our best size
                     top.Fit()
                 
 
@@ -554,6 +552,8 @@ class PyCollapsiblePane(wx.Panel):
         # update our state
         self._pPane.Show(not collapse)
         self._bCollapsed = collapse
+        self.InvalidateBestSize()
+
         self.Thaw()
 
         # update button label
@@ -603,7 +603,8 @@ class PyCollapsiblePane(wx.Panel):
         self._pButton.SetLabel(self.GetBtnLabel())
         self._pButton.SetInitialSize()
         self._pButton.Refresh()
-
+        self.InvalidateBestSize()
+        
         self.Layout()
 
 
@@ -625,6 +626,7 @@ class PyCollapsiblePane(wx.Panel):
         """
         
         self._pButton.SetFont(font)
+        self.InvalidateBestSize()
         self.Layout()    
 
 
@@ -656,6 +658,7 @@ class PyCollapsiblePane(wx.Panel):
         """
         
         self._expanderDimensions = width, height
+        self.InvalidateBestSize()
         if self._sz:
             self._sz.Layout()
         if self._pButton:
@@ -778,6 +781,7 @@ class PyCollapsiblePane(wx.Panel):
 
         if self._pPane:
             self._pButton.MoveBeforeInTabOrder(self._pPane)
+        self.InvalidateBestSize()
         self.Layout()