%gui tk hangs notebook #742

running %gui tk in any cell will produce a RuntimeWarning and hang the execution (no lines afterwards execute, execution hangs on cell)

C:\Users\norweeg\miniforge\envs\jupyter\lib\site-packages\ipykernel\eventloops.py:256: RuntimeWarning: coroutine 'Kernel.do_one_iteration' was never awaited
  self.func()
RuntimeWarning: Enable tracemalloc to get the object allocation traceback

strangely, this does not happen if you run %gui tk in IPython and the tkinter gui integration works fine. Only ipykernel has this problem.

Python 3.9.6
Tk 8.6.10
IPython 7.26.0
ipykernel 6.1.0
jupyterlab 3.1.6