Tkinter widgets not fully loading

[nortski]

It is a design problem. A while loop hogs the processor as it is always running, which doesn't allow for anything else to happen. You should seriously consider using a class for this so you can use instance objects for rftagID and anything else you want to keep. This also allows you to use after() instead of a while loop, which means you can do other things while scanCardLoop() is running.

""" A simple example that uses a counter to print to the screen
    from a function repeatedly called by after{}
    You can also enter data into the Entry while the counter function is running to show
     that other things can happen simultaneously
"""
import sys
if sys.version_info[0] < 3:
    import Tkinter as tk     ## Python 2.x
else:
    import tkinter as tk     ## Python 3.x

class TestClass():

   def __init__(self):
      self.top = tk.Tk()
      self.top.title("Test of After")
      self.top.geometry("200x150+10+10")

      tk.Label(self.top, text="Timer Test ").pack(side="left" )
      entry_1 = tk.Entry(self.top, width=10)
      entry_1.pack(side="left")
      entry_1.focus_set()

      ## self.ctr is an instance object, so retains it's value
      self.ctr = 1
      self.printit()
      self.top.mainloop()

   def printit(self):
      print("print 1", self.ctr)
      self.ctr += 1

      ## simulate if a condition is True
      if self.ctr < 100:
          self.top.after(100, self.printit)
      else:
          print("\nloop ended")
          self.top.quit()

##====================================================================
if __name__ == '__main__':
    CT=TestClass() 
    ## tkinter has exited. This shows how to get the value of a variable.
    print("\ncounter's value is %d" % (CT.ctr))

I ended up removing the infinite while loop and used the after() method instead. Works fine now thanks!