Avoid multiple windows of the same kind

[backermaster]

My goal is to have an interactive bar chart. I want to open a window containing a text. This shall happen when the user clicks on one of the bars. I started playing around a bit. In the following example, if you click on the left bar a window containing a text pops up. The problem I have, I only want to have the window opening once. So if you click a second time on the left bar, I don't want to open a second window. Therefore my question, how can I check if the window already exists and avoid multiple windows of the same kind.

Thank you very much for your help.

def on_press(event):
    cont,att = rect[0].contains(event)
    if cont == True:
        win = tk.Tk()
        label1 = ttk.Label(win, text ="Test1").grid(column=0,row=0)
        label2 = ttk.Label(win, text ="Test2").grid(column=0,row=1)
        label3 = ttk.Label(win, text ="Test3").grid(column=0,row=2)


fig = plt.figure()
ax = fig.add_subplot(111)
x = [1,2,3]
y = [10,20,5]
rect = ax.bar(x,y)



test = rect[0].figure.canvas.mpl_connect('button_press_event', on_press)

plt.show()

[Gribouillis]

You can add a boolean to remember if the window was already created

def on_press(event):
    if on_press.window_created:
        return
    cont,att = rect[0].contains(event)
    if cont == True:
        win = tk.Tk()
        on_press.window_created = True
        label1 = ttk.Label(win, text ="Test1").grid(column=0,row=0)
        label2 = ttk.Label(win, text ="Test2").grid(column=0,row=1)
        label3 = ttk.Label(win, text ="Test3").grid(column=0,row=2)
on_press.window_created = False
...