Bug summary

After figure is saved using PdfPages matplot lib shows error when trying to use figure.show(0:
"AttributeError: Figure.show works only for figures managed by pyplot, normally created by pyplot.figure()"
This is new as it worked fine in matplotlib 3.6.3

Code for reproduction

import matplotlib as mpl
import matplotlib.pyplot as plt
from matplotlib.backends.backend_pdf import PdfPages

r_fig = plt.figure('Results', layout='tight')
r_fig.set_size_inches(8,6)
r_ax1 = plt.subplot(221)
r_ax2 = plt.subplot(222)
r_ax1.plot([1,2,3],[1,2,3])
r_ax2.plot([1,2,3],[2,4,6])

pdff = PdfPages("C:\\Data\\Python\\r_file.pdf")
pdff.savefig(r_fig)
pdff.close()

r_fig.show()

Actual outcome

AttributeError: Figure.show works only for figures managed by pyplot, normally created by pyplot.figure()

Expected outcome

figure shown

Additional information

No response

Operating system

Windows 11

Matplotlib Version

3.8.3

Matplotlib Backend

TkAgg

Python version

3.11.8

Jupyter version

No response

Installation

pip