tkinter: using scrollbars on a canvas

Your scrollbars need to have the Frame as a parent, not the Canvas:

from tkinter import *
root=Tk()
frame=Frame(root,width=300,height=300)
frame.pack(expand=True, fill=BOTH) #.grid(row=0,column=0)
canvas=Canvas(frame,bg='#FFFFFF',width=300,height=300,scrollregion=(0,0,500,500))
hbar=Scrollbar(frame,orient=HORIZONTAL)
hbar.pack(side=BOTTOM,fill=X)
hbar.config(command=canvas.xview)
vbar=Scrollbar(frame,orient=VERTICAL)
vbar.pack(side=RIGHT,fill=Y)
vbar.config(command=canvas.yview)
canvas.config(width=300,height=300)
canvas.config(xscrollcommand=hbar.set, yscrollcommand=vbar.set)
canvas.pack(side=LEFT,expand=True,fill=BOTH)

root.mainloop()

The reason why this works is due to how pack works. By default it will attempt to shrink (or grow) a container to exactly fit its children. Because the scrollbars are children of the canvas in the original example, the canvas shrinks to fit.

If you want the scrollbars to appear inside the canvas, the trick is to use an extra frame. Place the canvas and scrollbars in this inner frame, turn the borders off of the canvas and on for the frame. Set the background of the frame to be the same as the canvas and it will appear that the scrollbars are inside the canvas.