Tkinter Treeview style

Question

Why my table isn't changing style according to what I defined? I tried using style and map and it didn't change anything. It seems that the only thing that works is the Theme configuration. also the scroller isn't show in the Treeview.

from tkinter import *
from tkinter import ttk

class Dashboard:

def __init__(self, filterdDf):

    self.filterdDf = filterdDf

    root =Tk()
    root.title('Dashboard')
    root.geometry('1300x690')
    root.resizable(False, False)

    frame = Frame(root, width=1100, height=690)
    frame.configure(background="gray28")
    frame.pack(fill=BOTH, expand=True)

    rows = len(filterdDf)

    tree = ttk.Treeview(root, columns=(1, 2), height=rows, show="headings")
    tree.pack(side='left')
    tree.place(x=700, y=150)

    #Add some style:
    style = ttk.Style()

    style.theme_use("clam")

    style.configure("Treeview",
                    background="silver",
                    foreground="black",
                    rowheight=55,
                    fieldbackground="silver")

    #Change selected color:
    style.map("Treeview",
              background=[('selected', 'green')])

    tree.heading("#0", text="Label", anchor=W)
    tree.heading("#1", text="Approach", anchor=CENTER)
    tree.heading("#2", text="Recommendation", anchor=CENTER)

    tree.column("#0", width=120, minwidth=25)
    tree.column("#1", width=300, minwidth=25, anchor=W)
    tree.column("#2", width=150, minwidth=25, anchor=CENTER)

    scroll = ttk.Scrollbar(frame, orient="vertical", command=tree.yview)
    scroll.pack(side='right', fill='y')

    tree.configure(yscrollcommand=scroll.set)

    for i in range(rows):
        tree.insert(parent='', index='end', values=(filterdDf[('Approaches', 'All')].iloc[i],
                                       filterdDf[('Recommendation Level', '')].iloc[i]))

    root.mainloop()

This is how my Treeview looks like: 2 columns filled with data. Thanks!

This is how it suppose to look with the style configuration (diffrent data but same configurations):