Test code

from tkinter import *

root = 0
wrapper = 0
navigationButtons = []
helpLabel = 0

def onMouseEnter(par_event, par_option):
    helpLabel.configure(text = par_option.desc)
    return

def onMouseLeave(par_event):
    helpLabel.configure(text = '')
    return

class Option:
    def __init__(self, par_name, par_desc):
        self.name = par_name
        self.desc = par_desc
        #self.button = Button(wrapper, text = self.name, bg = '#004A7F', fg = 'white')
        #self.button.bind('<Enter>', lambda par_event: onMouseEnter(par_event, self))
        #self.button.bind('<Leave>', lambda par_event: onMouseLeave(par_event))

class Mode():
    def __init__(self):
        self.options = []
        self.options.append(Option('Option1', 'Desc1'))
        self.options.append(Option('Option2', 'Desc2'))
        self.options.append(Option('Option3', 'Desc3'))
        self.options.append(Option('Option4', 'Desc4'))
        self.options.append(Option('Option5', 'Desc5'))

class GUIMode(Mode):
    def __init__(self):
        super(GUIMode, self).__init__()

    def run(self):
        global root
        global wrapper
        global navigationButtons
        global helpLabel

        root = Tk()

        wrapper = PanedWindow(root, orient = VERTICAL)

        for iOption in self.options:
            iOption.button = Button(wrapper, text = iOption.name, bg = '#004A7F', fg = 'white')
            iOption.button.bind('<Enter>', lambda par_event: onMouseEnter(par_event, iOption))
            iOption.button.bind('<Leave>', lambda par_event: onMouseLeave(par_event))

        helpLabel = Label(wrapper)

        for iOption in self.options:
            wrapper.add(iOption.button)

        wrapper.add(helpLabel)

        wrapper.grid()
        root.mainloop()

        return

GUIMode().run()