from tkinter import *

root = Tk()

#root.minsize(300, 300)

filenametext = Entry(root, bg='#f00')
filenametext.place(x=0, y=0)

text = StringVar()
filenametext['textvariable'] = text

button = Button(root, text='Открыть')
button.place(x=100, y=0)

button2 = Button(root, text='Открыть2')
button2.place(x=100,y=100)

root.mainloop()