[Python] Why does matplotlib draw updates for the first interactive plot I show, but not the...

I'm trying to show two interactive plots. The second plot is displayed after the first plot is closed. In this minimal example, the interactive part just draws a dot wherever the user clicks and prints the coordinates to the console.

import matplotlib.pyplot as plt

def onclick(event):
# This prints both times
print(event.xdata, event.ydata)
# This only works the first time
plt.scatter(event.xdata, event.ydata)

for i in range(2):
plt.plot([1, 2, 3, 4])
plt.gca().figure.canvas.mpl_connect('button_press_event', onclick)
with plt.ion():
plt.show(block=True)


Using the code above, dots don't show up on the second plot. It still prints the coordinates, so the event is firing; it's just not drawing. Everything else works.

Things I've tried that didn't help:

• Different backends (Qt, Tk)
• plt.close() as the last step inside loop
• plt.pause(1) as the last step inside loop
• Using plt.ion() and plt.ioff() instead of the context manager
• Manually detaching the event at the end of the loop, using canvas.mpl_disconnect(cid) with the cid returned from mpl_connect
• plt.draw() & plt.pause(1) to try and force updates
• Copying and pasting the same code twice instead of using a loop
• Using fig, ax = plt.subplots() in the loop and ax.scatter() in the onclick handler to explicitly plot to the same axes

I'm using matplotlib 3.9.4 in Python 3.9.20 for compatibility with things beyond my control.

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