Sorry but I can't help you with this, personally I would have left out almost all of the row and column configuring code and start by just testing as you add each frame, entry and button. I don't understand why you have added so much complication and find it hard to see what value there is in it.
from tkinter import * from tkinter import ttk root = Tk() root.title("Unit-20180109") frame1 = ttk.Frame(root, padding="10 10 10 10") frame1.grid()#(column=0, row=0, sticky=(N, W, E, S)) #frame1.columnconfigure(0, weight=1) #frame1.rowconfigure(0, weight=1) notebook1 = ttk.Notebook(frame1, width="800", height="600") screen1 = ttk.Frame(notebook1) notebook1.add(screen1, text="screen 1") notebook1.grid() screen1.grid() #_columnconfigure(0, weight=1) #screen1.grid_rowconfigure(0, weight=1) combobox1var = StringVar() combobox1=ttk.Combobox(screen1, textvariable=combobox1var, values=("Provide an input ...", "a", "b", "c", "d", "e", "f"), state="readonly" ) combobox1.current(0) combobox1.grid(padx=10, row=3, column=0, rowspan=1, columnspan=4, sticky="new" ) entry1var=StringVar() entry1=ttk.Entry(screen1, textvariable=entry1var) entry1.grid(padx=10, row=4, column=0) #, rowspan=1, columnspan=2, sticky="new") button1= ttk.Button(screen1, text="a") button2= ttk.Button(screen1, text="b") button1.grid(padx=10, row=5, column=0) #, rowspan=1, columnspan=1, sticky="new") button2.grid(padx=10, row=6, column=0) #, rowspan=1, columnspan=1, sticky="new") root.mainloop()I edited out a lot of what you put but don't know if it's nearer to what you seem to want.