diff --git a/__pycache__/definitions.cpython-311.pyc b/__pycache__/definitions.cpython-311.pyc
index 5c90a03..29fae7f 100644
Binary files a/__pycache__/definitions.cpython-311.pyc and b/__pycache__/definitions.cpython-311.pyc differ
diff --git a/__pycache__/users.cpython-311.pyc b/__pycache__/users.cpython-311.pyc
new file mode 100644
index 0000000..1fb4698
Binary files /dev/null and b/__pycache__/users.cpython-311.pyc differ
diff --git a/ui.py b/ui.py
index ea4b0a8..4cfebe5 100644
--- a/ui.py
+++ b/ui.py
@@ -10,83 +10,99 @@ from definitions import app_title, app_version
 
 # Pinpad
 
-def win_pinpad():
+class win_pinpad(tk.Toplevel):
+    def __init__(self, parent):
+        super().__init__(parent)
 
-    def update_time():
-        string_time = strftime('%A, der %d.%m.%Y - %H:%M:%S')
-        nonlocal digital_clock
-        digital_clock.config(text=string_time)
-        digital_clock.after(1000, update_time)
+        def update_time():
+            string_time = strftime('%A, der %d.%m.%Y - %H:%M:%S')
+            nonlocal digital_clock
+            digital_clock.config(text=string_time)
+            digital_clock.after(1000, update_time)
 
-    root = tk.Tk()
-    root.title(app_title + " " + app_version)
-    root.eval('tk::PlaceWindow . center')
+        self.title(app_title + " " + app_version)
 
-    # Digital clock label configuration
-    digital_clock = tk.Label(root)
-    digital_clock.grid(row=0, column=0, columnspan=3, padx=10, pady=10)
-    # Initial call to update_time function
-    update_time()
+        # Digital clock label configuration
+        digital_clock = tk.Label(self)
+        digital_clock.grid(row=0, column=0, columnspan=3, padx=10, pady=10)
+        # Initial call to update_time function
+        update_time()
 
-    # Benutzernummer
-    def usernr_changed(UserNr):
-        nonlocal usernr
-        if len(str(usernr.get())) > 0:
-            buttons["OK"].configure(state="active")
-        else:
-            buttons["OK"].configure(state="disabled")
+        # Benutzernummer
+        def usernr_changed(UserNr):
+            nonlocal usernr
+            if len(str(usernr.get())) > 0:
+                buttons["OK"].configure(state="active")
+            else:
+                buttons["OK"].configure(state="disabled")
 
 
-    tk.Label(root, text="Benutzernummer:").grid(row=1, column=0)
-    UserNr = tk.StringVar()
-    UserNr.trace("w", lambda name, index, mode, UserNr=UserNr: usernr_changed(UserNr))
-    usernr = tk.Entry(root, width=10, textvariable=UserNr)
-    usernr.grid(row=1,column=1)
+        tk.Label(self, text="Benutzernummer:").grid(row=1, column=0)
+        UserNr = tk.StringVar()
+        UserNr.trace("w", lambda name, index, mode, UserNr=UserNr: usernr_changed(UserNr))
+        usernr = tk.Entry(self, width=10, textvariable=UserNr)
+        usernr.grid(row=1,column=1)
 
-   # Pinpad
+       # Pinpad
 
-    def buttonPress(key):
+        def buttonPress(key):
 
-        nonlocal usernr
-        if type(key) is int:
-            if key < 10:
-                usernr.insert('end', str(key))
-        if key =="OK":
-          print("OK pressed")
-        if key == "<-":
-            usernr.delete(usernr.index("end") - 1 )
-        if len(usernr.get()) > 0:
-            buttons["OK"].configure(state="active")
-        else:
-            buttons["OK"].configure(state="disabled")
+            nonlocal usernr
+            if type(key) is int:
+                if key < 10:
+                    usernr.insert('end', str(key))
+            if key =="OK":
+              print("OK pressed")
+            if key == "<-":
+                usernr.delete(usernr.index("end") - 1 )
+            if len(usernr.get()) > 0:
+                buttons["OK"].configure(state="active")
+            else:
+                buttons["OK"].configure(state="disabled")
 
-    # Buttons definieren
-    button_width = 7
-    button_height = 3
-    pinframe = tk.Frame(root)
-    pinframe.grid(row=2, column=0, columnspan=3, padx=10, pady=10)
-    buttons = { }
+        # Buttons definieren
+        button_width = 7
+        button_height = 3
+        pinframe = tk.Frame(self)
+        pinframe.grid(row=2, column=0, columnspan=3, padx=10, pady=10)
+        buttons = { }
 
-    keys = [
-        [ 1, 2, 3],
-        [ 4, 5, 6],
-        [ 7, 8, 9],
-        [ "<-", 0, "OK"]
-    ]
+        keys = [
+            [ 1, 2, 3],
+            [ 4, 5, 6],
+            [ 7, 8, 9],
+            [ "<-", 0, "OK"]
+        ]
 
-    for y, row in enumerate(keys, 1):
-        for x, key in enumerate(row):
-            button = tk.Button(pinframe, width=button_width, height=button_height, text=key, command=lambda key=key: buttonPress(key))
-            button.grid(row=y, column=x)
-            buttons[key] = button
+        for y, row in enumerate(keys, 1):
+            for x, key in enumerate(row):
+                button = tk.Button(pinframe, width=button_width, height=button_height, text=key, command=lambda key=key: buttonPress(key))
+                button.grid(row=y, column=x)
+                buttons[key] = button
 
-    buttons["OK"].configure(state="disabled")
+        buttons["OK"].configure(state="disabled")
 
-    usernr.focus_set()
+        usernr.focus_set()
 
-    # Tkinter main loop
+class mainwindow(tk.Tk):
+    def __init__(self):
+        super().__init__()
 
-    root.mainloop()
+        self.geometry('300x200')
+        self.title('Main Window')
+
+        # place a button on the root window
+        tk.Button(self,
+                   text='Login Window',
+                   command=self.open_window).pack(expand=True)
+
+    def open_window(self):
+        window = win_pinpad(self)
+        window.grab_set()
+
+
+if __name__ == "__main__":
+    app = mainwindow()
+    app.mainloop()
 
-def win_userselection():