title: Scrollbar is Not getting active in Python TK
body: <p>I am Creating Multiple tab window using Notebook and in one of tab "Check Box" will created dynamically depending on the values in the Excel . (I am able to read values from Excel and Create the Check Box) . The Number of Check box will be equal to number values in the excel .</p>
  
  <p>In my Excel I have values from <strong><em>1 to 30</em></strong> . But  i am seeing values till <strong><em>1 to 11</em></strong> and other values are down in the UI , But scroll Bar is not active . </p>
  
  <p>Please help me with this . </p>
  
  <pre><code>import tkinter as tk
  
  from dicttoxml import dicttoxml
  import xlrd
  
  
  import GetValueFromExcel
  from GetValueFromExcel import ExcelValue
  from array import array
  from tkinter import *
  from tkinter import ttk, Button
  from tkinter import *
  
  root = Tk()
  CheckBoxSelection=[]
  NameOfVariable=[]
  KeyName=[]
  SelectedCheckbox=[]
  dict={}
  frame_main = tk.Frame(root)
  frame_main.grid(sticky='news')
  canvas=tk.Canvas()
  
  class UICreation():
  
      def __init__(self):
          print ("I m in __init__")
          self.nb=ttk.Notebook(frame_main)
          self.page1=ttk.Frame(self.nb)
          self.page2=ttk.Frame(self.nb)
  
  
      def tabcreation(self):
          print ("I M in Tab Creation")
          self.nb.add(self.page1,text="Select")
          canvas = tk.Canvas(self.page1)
          canvas.grid(row=0, column=0, sticky="news")
          vsb = tk.Scrollbar(self.page1, orient="vertical", command=canvas.yview)
          vsb.grid(row=0, column=1, sticky='ns')
          canvas.configure(yscrollcommand=vsb.set)
          canvas.config(scrollregion=canvas.bbox("all"))
          f = tk.Frame(canvas)
          canvas.create_window((200, 0), window=f, anchor="n")
          self.nb.add(self.page2,text="Add")
          self.nb.grid(sticky=N)
          print ("I M in checkBox")
          ListNumber=len(List_key)
          print (ListNumber)
          for value in range(0,ListNumber, 1):
               NameOfVariable= "checkBox" + str(value)
               CheckBoxSelection.append("var"+str(value))
               CheckBoxSelection[value]=IntVar()
               NameOfVariable = Checkbutton(f, text=str(List_key[value]),variable=CheckBoxSelection[value])
               Checkbutton()
               NameOfVariable.grid(sticky=NW)
               NameOfVariable.cget("text")
               KeyName.append(NameOfVariable.cget("text"))
  
      def button(self):
           button = Button(frame_main, text="Submit", command=self.OnButtonClick)
           button.grid(sticky=NW)
  
      def OnButtonClick(self):
          index = 0
          SelectedCheckboxValue=[]
          for st in (CheckBoxSelection):
              if st.get():
                  SelectedCheckboxKey=KeyName[index]
                  SelectedCheckboxValue=GetValueFromExcel.row_data_dict[SelectedCheckboxKey]
                  index+=1
                  dict={
                  "Properties": {"id": "ConnectJetSerialNumber"+SelectedCheckboxKey,"value":SelectedCheckboxValue[0],"PrinterName":SelectedCheckboxValue[1],"PrinterName2":SelectedCheckboxValue[2]}
                       }
                  print(dict)
                  xml = dicttoxml(dict, custom_root='test', attr_type=False)
                  file=open(r"C:\SmallVille\SmallVilleAutoConfigGUI\Selected.xml","a")
                  file.write(str(xml))
              else:
                  index+=1
  
  
  if __name__ == '__main__':
      ui = UICreation()
      ev = GetValueFromExcel.ExcelValue()
      t=ev.readExcelValue()
      print("I am before print t")
      print(t)
      print("I am before list")
      List_key= list(t.keys())
      print (List_key)
      ui.tabcreation()
      ui.button()
      root.mainloop()
  </code></pre>
  
  <p>UI Screen Shoot also attached
  <a href="https://i.stack.imgur.com/7tW4V.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/7tW4V.png" alt="My UI"></a></p>