Merge pull request matplotlib#583 from dhyams/wx-check-clipboard

Check before opening clipboard in wx

Author: mdboom

lib/matplotlib/backends/backend_wx.py

@@ -777,10 +777,13 @@ def Copy_to_Clipboard(self, event=None):
         "copy bitmap of canvas to system clipboard"
         bmp_obj = wx.BitmapDataObject()
         bmp_obj.SetBitmap(self.bitmap)
-        wx.TheClipboard.Open()
-        wx.TheClipboard.SetData(bmp_obj)
-        wx.TheClipboard.Close()
-        wx.TheClipboard.Flush()
+        
+        if not wx.TheClipboard.IsOpened(): 
+           open_success = wx.TheClipboard.Open()
+           if open_success:
+              wx.TheClipboard.SetData(bmp_obj)
+              wx.TheClipboard.Close()
+              wx.TheClipboard.Flush()
 
     def Printer_Init(self):
         """