Why am i receiving a KeyError when interacting with the second window that appears with PySimpleGUI?

Question

The user can search for names in the database with the search box and select the name they want. a second window will appear for them to enter information. Any interaction with the second window causes a KeyError for values["IN"].

import PySimpleGUI as sg

pt_list = ["Test 1", "Test 2", "Test 3"]

def make_window1():
    layout = [
        [sg.Button("Add New Patient", key = "ADD"), sg.Button("Remove Patient", key = "RMV")],
        [sg.Input("Search patient name", key = "IN", enable_events = True), sg.Button("Search", key = "SEARCH")],
        [sg.Listbox(pt_list, expand_x = True, expand_y = True, key = "LIST", enable_events = True)]
        ]

    return sg.Window("WINDOW1", layout, finalize = True)

def make_window2():
    layout = [
        [sg.Text("A second window has appeared.")],
        [sg.Button("Close 2nd window")],
        ]

    return sg.Window("WINDOW2", layout, finalize = True)

def main():
    window2 = None
    window1 = make_window1()

    while True:
        window, event, values = sg.read_all_windows()
        if event == sg.WIN_CLOSED and window == window1 or event == "Quit":
            break

        #Patient selcetion list
        # if a keystroke entered in search field
        if values['IN'] != '':                         
            search = values['IN']
            # do the filtering
            new_values = [x for x in pt_list if search in x]
            # display in the listbox
            window['LIST'].update(new_values)     
        else:
        # display original unfiltered list
            window['LIST'].update(pt_list)
        # if a list item is chosen, switch to patient folder
        if event == 'LIST' and len(values['LIST']):
            window2 = make_window2()
            window1.hide()

        if window == window2 and (event in (sg.WIN_CLOSED, 'Save & Close')):
            window2.close()
            window2 = None
            window1.un_hide()
    window1.close()

#Running the program
if __name__ == '__main__':
    main()

If the second window is not called it works as intended but i cannot think of why calling the second window would cause the KeyError, i dont see the connection.

Traceback (most recent call last):
  File "C:\Users\ps2ee\Downloads\Testmulti.py", line 59, in <module>
    main()
  File "C:\Users\ps2ee\Downloads\Testmulti.py", line 36, in main
    if values['IN'] != '':
KeyError: 'IN'

Answer 1

i was able to get it to work with the following.

 if window == window1 and values['IN'] != '':                         
        search = values['IN']
        # do the filtering
        new_values = [x for x in pt_list if search in x]
        # display in the listbox
        window1['LIST'].update(new_values)     
    else:
    # display original unfiltered list
        window1['LIST'].update(pt_list)
    # if a list item is chosen, switch to patient folder
    if event == 'LIST' and len(values['LIST']):
        window2 = make_window2()
        window1.hide()

I wasn't checking for which window object values["IN"] was in. thank you @JasonYang for pointing me in the right direction