ec_global5.py

# taken from: https://stackoverflow.com/questions/5600370/python-matplotlib-add-and-remove-text-to-figure-using-button-events#answer-5600964

txt = None

def onclick(event):
    global txt  # why global txt? because there's a variable assignment
    txt = plt.text(event.xdata, event.ydata, 'TESTTEST', fontsize=8)
    fig.canvas.draw()

def offclick(event):
    txt.remove()  # why there's no global txt? because there's no variable assignment
    fig.canvas.draw()

fig.canvas.mpl_connect('button_press_event', onclick)
fig.canvas.mpl_connect('button_release_event', offclick) 

plt.show()