Repository navigation
Using the recent ipykernel 7.x causes plots to not show up from ipympl widgets. #1476
Description
After upgrading to recent versions of jupyterlab, ipympl and ipykernel I observed on different systems, either Windows 11 or Linux, that ipympl figures would not show up sometimes without an explicit plt.show() at the end of the cell.
While this looked to me at first glance like an ipympl bug because it does not appear using inline figures it turns out that downgrading ipykernel to 6.3.1 completely solves the issue.
Here is the the original report with more details: matplotlib/ipympl#609
I saw that ipykernel>=7 has quite a few changes regarding matplotlib, so I assume this is a unwanted side-effect of these changes.
Activity
clemisch commentedon Apr 21, 2026
I'm also experiencing the same issue on
ipykernel==7.2.0. Downgrading to e.g.ipykernel==6.31.0fixes it.Additionally I'm experiencing weird behavior when executing multiple cells in succession (hitting Shift+Enter multiple times). Sometimes all cells keep on indicating they're busy (
[*]) but never return. At the same time the kernel indicator on the top right shows "Kernel idle". If I reload the browser tab the cells are shown as never executed.This seems to happen even for cells containing no mpl related code / figures at all.
Again, this is fixed when downgrading to e.g.
ipykernel==6.31.0.Er-Rajas commentedon Sep 29, 2026
I am also facing the same problem
I downgraded to
ipykernel==6.31.0