Trying to extend this frame to the bottom but can't get it to work

Question

I have 1 window with 2 frames inside, and i am trying to make it that the left frame (frame_side) is filled to the bottom of the screen even if you expand it. But since i don't use .pack() I tried using .rowconfigure() but it still doesn't work.

Blue area needs to be extended

window.geometry('950x650')
    window.resizable(height=None, width=None)

    frame_side = Frame(window, borderwidth=5, bg='gray')
    frame_side.grid(column=0, row=0, rowspan=100)

    frame_main = Frame(window)
    frame_main.grid(column=1, row=0, rowspan=100)

    lbl = Label(frame_main, text="Password Vault")
    lbl.grid(column=1, row=0)

    img1o = Image.open("images/plus.png")
    resize_img1 = img1o.resize((24, 24))
    img1 = ImageTk.PhotoImage(resize_img1)

    img2o = Image.open("images/gear_hollow.png")
    resize_img2 = img2o.resize((24, 24))
    img2 = ImageTk.PhotoImage(resize_img2)

    img3o = Image.open("images/add.png")
    resize_img3 = img3o.resize((24, 24))
    img3 = ImageTk.PhotoImage(resize_img3)

    btn = Button(frame_side, image=img1, command=addEntry)
    btn.image = img1
    btn.grid(column=0, row=3)

    btn1 = Button(frame_side, image=img2, command=openSettings)
    btn1.image = img2
    btn1.grid(column=0, row=0)

    btn2 = Button(frame_side, image=img3, command=openUser)
    btn2.image = img3
    btn2.grid(column=0, row=1)

    fill = Label(frame_side, bg='gray')
    fill.grid(column=0, row=2)

    fill1 = Label(frame_side, bg='gray')
    fill1.grid(column=0, row=4, sticky='ns')

    frame_side.grid_rowconfigure(0, weight=1)   # tried to configure the frame
    fill1.grid_rowconfigure(0, weight=1)        # and the label itself

Answer 1

I have found the solution:

• I first used rowconfigure with weight 1 on row 0 because otherwise the other rowconfigure wont work.
• Then i used columnconfigure weight 1 for column 0, and columnconfigure weight 1000 for column 1, so the column will stay thin even on full screen.
• And then I needed to do columnconfigure weight 1 column 1 inside the frame_side and rowconfigure weight 1000 on the last row for the same reason in the main window.

Full code:

window.geometry('950x650')
window.resizable(height=None, width=None)
window.rowconfigure(0, weight=1)
window.columnconfigure(0, weight=1)
window.columnconfigure(1, weight=1000)
frame_side = Frame(window, borderwidth=5, bg='gray')
frame_side.grid(column=0, row=0, sticky='NSEW')
frame_side.rowconfigure(8, weight=1000)
frame_side.columnconfigure(0, weight=1)

Don't forget to put sticky='NSEW' in the row and the frame