Any Tkinker based rich text widget?

[Sullivan WxPyQtKinter]

yes, I have tried Text Widget for quite some time. However, its speed
is far from satisfying.

When it holds more than 20,000 characters, it starts to response quite
slow. When you drag your mouse over some text to select, the selection
is usually done after 0.5second or so. My intent to use this widget is
to compose and process report as long as 30 to 60 pages.

Is it the problem of the Text widget or my usage? the following is the
code for testing Text widget. Run it and paste 20,000 characters, and
then it is retardant....

=======Code Start=========
from Tkinter import *
root=Tk()
root.title("Lab Report Editor")

text=Text(root,height=25)
text.grid(row=0,column=0,sticky=N+S+W+E)

root.columnconfigure(0,weight=1)
root.rowconfigure(0,weight=1)
root.mainloop()
===========Code End===============