Issue #1658: dict size is changing during iteration in tkinter.BaseWidget and
tkinter.scrolledtext.ScrolledText.

Reviewed by Amaury Forgeot d'Arc
diff --git a/Lib/tkinter/__init__.py b/Lib/tkinter/__init__.py
index faca78f..bb014b3 100644
--- a/Lib/tkinter/__init__.py
+++ b/Lib/tkinter/__init__.py
@@ -1913,11 +1913,9 @@
             cnf = _cnfmerge((cnf, kw))
         self.widgetName = widgetName
         BaseWidget._setup(self, master, cnf)
-        classes = []
-        for k in cnf.keys():
-            if isinstance(k, type):
-                classes.append((k, cnf[k]))
-                del cnf[k]
+        classes = [(k, v) for k, v in cnf.items() if isinstance(k, type)]
+        for k, v in classes:
+            del cnf[k]
         self.tk.call(
             (widgetName, self._w) + extra + self._options(cnf))
         for k, v in classes:
diff --git a/Lib/tkinter/scrolledtext.py b/Lib/tkinter/scrolledtext.py
index 084c3bf..35767e6 100644
--- a/Lib/tkinter/scrolledtext.py
+++ b/Lib/tkinter/scrolledtext.py
@@ -19,11 +19,10 @@
             cnf = {}
         if kw:
             cnf = _cnfmerge((cnf, kw))
-        fcnf = {}
-        for k in cnf.keys():
-            if isinstance(k, type) or k == 'name':
-                fcnf[k] = cnf[k]
-                del cnf[k]
+        fcnf = {k:v for k,v in cnf.items() if isinstance(k,type) or k=='name'}
+        for k in fcnf.keys():
+            del cnf[k]
+
         self.frame = Frame(master, **fcnf)
         self.vbar = Scrollbar(self.frame, name='vbar')
         self.vbar.pack(side=RIGHT, fill=Y)