Interactive Window input window hang 5+ seconds on intellisense popup

[IanMatthewHuff]

I'm working with Python 3.7.3 64-bit and I'm using code like the following:
`#%% Imports
import numpy as np
import pandas as pd
from sys import getsizeof

#%% Some big variables
with open('D:\github\Samples\DSPlayground\Books\Content\Moby.txt', 'r', encoding='utf-8') as textFile:
big_string = textFile.read()

big_nparray = np.linspace(0,100000, 50000, endpoint=True)
big_dataframe = pd.DataFrame(big_nparray)
big_series = big_dataframe[0]
big_list = [x ** 2 for x in range(0,100000)]
big_set = set(big_list)
big_dict = {}
big_int = 9999999
big_float = 99.999999
big_complex = complex(1,1)
for value in big_list:
big_dict[value] = value / 2
big_tuple = 1,2,3,4,5,6,7,8,9

big_var_list = ['big_string', 'big_nparray', 'big_dataframe', 'big_series', 'big_list',
'big_set', 'big_dict', 'big_int', 'big_float', 'big_complex','big_tuple']
testing = 'testing'`

Note: just remove the big string line as you won't have that file. In the input window typing in big_ causes a delay of about 5 seconds when loading the completion list. This happens about 50% of the time and also happens when deleting the string. During this time the UI is totally hung.