how do i add a dropdown menu display GOES image on a tkinter popup window

im trying to add a dropdown menu on my tkinter popup window but when ever i run it on my visual studio code ide nothing displays but when i run the code by it self on jupyter everything work fine so what is going on

def btn4():
 newWindow4 = Toplevel(root)
 newWindow4.title(GOES NOAA V1.0 )
 newWindow4.geometry(1620x1300)
 fig = plt.figure(figsize=(6, 6))
 canvas = FigureCanvasTkAgg(fig, master=newWindow4)
 canvas.get_tk_widget().pack(side=tkinter.TOP, fill=tkinter.BOTH, expand=1)

channel_list = {u'1 - Blue Band 0.47 \u03BCm': 1,
                u'2 - Red Band 0.64 \u03BCm': 2,
                u'3 - Veggie Band 0.86 \u03BCm': 3,
                u'4 - Cirrus Band 1.37 \u03BCm': 4,
                u'5 - Snow/Ice Band 1.6 \u03BCm': 5,
                u'6 - Cloud Particle Size Band 2.2 \u03BCm': 6,
                u'7 - Shortwave Window Band 3.9 \u03BCm': 7,
                u'8 - Upper-Level Tropo. WV Band 6.2 \u03BCm': 8,
                u'9 - Mid-Level Tropo. WV Band 6.9 \u03BCm': 9,
                u'10 - Low-Level WV Band 7.3 \u03BCm': 10,
                u'11 - Cloud-Top Phase Band 8.4 \u03BCm': 11,
                u'12 - Ozone Band 9.6 \u03BCm': 12,
                u'13 - Clean IR Longwave Band 10.3 \u03BCm': 13,
                u'14 - IR Longwave Band 11.2 \u03BCm': 14,
                u'15 - Dirty Longwave Band 12.3 \u03BCm': 15,
                u'16 - CO2 Longwave IR 13.3 \u03BCm': 16}

region = Select(
    options=['Mesoscale-1', 'Mesoscale-2', 'CONUS', 'PuertoRico', 'FullDisk'],
    description='Region:',
)

channel = Dropdown(
   options=channel_list,
   value=9,
   description='Channel:',)```