#######################################################
# Case 1: 100% cpu
import matplotlib.pyplot as plt
fig = plt.figure()
plt.plot(range(5))
plt.show()
# after closing the window
import pandas              # starting 100% CPU utilization

#######################################################
# Case 2: 100% cpu
import matplotlib.pyplot as plt
import pandas as pd

# No CPU utilization at the moment

fig = plt.figure()
df = pd.DataFrame(range(5))

plt.plot(df[0])           # with this, CPU utilization is 100%.
plt.show()                 # the same

# after closing the window, still 100%

#######################################################
# Case 3: no issue.
import matplotlib.pyplot as plt
fig = plt.figure()
plt.plot(range(5))
plt.show()              # strangely, this has no problem.