matplotlib slider not working when embedded in pyqt6 application

Question

I can't get the matplotlib slider to respond inside a PyQt6 application. Here is a sample program. I know there is no binding on the slider (that's not the problem). The problem is the slider itself doesn't respond to mouse events (ie. clicking, dragging).

I'm using python 3.10.12, matplotlib 3.8.2, PyQt6 6.6.1

import numpy as np

from matplotlib.backends.backend_qtagg import FigureCanvas
from matplotlib.backends.backend_qtagg import \
    NavigationToolbar2QT as NavigationToolbar
from matplotlib.backends.qt_compat import QtWidgets
from matplotlib.figure import Figure
from matplotlib.widgets import Slider

class ApplicationWindow(QtWidgets.QMainWindow):
    def __init__(self):
        super().__init__()
        self._main = QtWidgets.QWidget()
        self.setCentralWidget(self._main)
        layout = QtWidgets.QVBoxLayout(self._main)

        fig = Figure(figsize=(5, 3))
        static_canvas = FigureCanvas(fig)
        layout.addWidget(NavigationToolbar(static_canvas, self))
        layout.addWidget(static_canvas)

        self._static_ax = static_canvas.figure.subplots()
        t = np.linspace(0, 10, 501)
        self._static_ax.plot(t, np.tan(t), ".")

        fig.subplots_adjust(left=0.25)

        axamp = fig.add_axes([0.1, 0.25, 0.0225, 0.63])
        amp_slider = Slider(
            ax=axamp,
            label="Amplitude",
            valmin=0,
            valmax=10,
            valinit=6,
            orientation="vertical"
        )

        amp_slider.on_changed(self.slider_callback)
    
    def slider_callback(self):
        print("slider is changing")

if __name__ == "__main__":
    # Check whether there is already a running QApplication (e.g., if running
    # from an IDE).
    qapp = QtWidgets.QApplication.instance()
    if not qapp:
        qapp = QtWidgets.QApplication(sys.argv)

    app = ApplicationWindow()
    app.show()
    app.activateWindow()
    app.raise_()
    qapp.exec()

Answer 1

As per the comment by @relent95, I just needed to store a reference to the slider instance.

self.amp_slider = Slider(...)