My terminals are blank pages as shown in the attached screenshot, as in, no prompt. I had a large server running for the workshop earlier today, I had it in keep alive mode for 2h. I had not touched it in over 2 hours, came back, opened a new terminal, and it was blank. I have since restarted my server twice, and each time still a blank terminal.
Thanks for reporting this @jkrick. Can you try clearing your browser cache? If that doesn’t fix the problem, let us know what browser you’re using and we’ll look into it.
I just clicked back over to my fornax window and the terminal is working as expected. This was not the case 30 min. ago when I last checked it. So it took something between ~1.5 and 2.5 hours to clear itself. Some of that time with the server shutdown for ~15 min. or so to make sure I was getting a clean shutdown. Most of the rest of that time either restarting or just sitting with a small server open.
Did something happen in the last ~30 min. to clear it?
I am running Fornax in Safari on a Mac. I do not think it has anything to do with my local setup since I was inside Fornax, I could open files, do everything else, just not the terminal. I understand that non-repeatable things are difficult to track down, but this is quite frustrating. My guess is that this is somehow tied to the keep alive function, because it’s the first time I’ve seen this terminal behavior, and I use fornax most workdays, but don’t often use the keep alive.
I’m glad the issue cleared up. We’ll check to see if we can find what caused it.
This issue is not cleared up and is now repeatable. Every time I login in the past two days, I get blank terminals for tens of minutes. Core team: if this is just me, can we somehow reset my account?
I would like to underscore that I need terminals to do my work.
ok, claude has been debugging, and here is the current summary. Looks like it is a color rendering issue instead of a dead terminal issue. I am way out of my depth here on being able to confirm any of this, but I am now functional with switching themes and reloading an already open fornax session. Below is Claude’s summary. Please let me know if you want me to help debug anything.
Summary: JupyterLab terminals on fornax-jupyter:stable can render text
in a
color indistinguishable from the background, making a working terminal look
dead.
The shell is running fine the entire time — output is only readable when
selected
with the mouse.
Impact: Presents as “Fornax terminals are broken.” I lost parts of two
days to
it before discovering by accident that highlighting revealed the text. Anyone
who
doesn’t stumble onto that concludes the platform doesn’t work.
Environment: Safari on macOS; image fornax-jupyter:stable; JupyterLab on
the
default Light theme; TERM=xterm-256color, COLORTERM unset.
Observed: Terminal opens with a black background and near-black text. Over
tens of minutes the text flipped between visible and invisible several times
with
no action on my part. Both occurrences were the first terminal opened after a
fresh server spawn; a warm page reload later rendered correctly (white
background,
readable text).
Likely cause (hypothesis — not confirmed in devtools): the terminal theme
defaults to "inherit" (schema default confirmed at
/opt/jupyter/share/jupyter/lab/schemas/@jupyterlab/terminal-extension/plugin. json),
so xterm.js reads --jp-layout-color0 / --jp-ui-font-color0 from CSS rather
than
using fixed colors. On the Light theme that should yield a white background;
we got
black, which is xterm.js’s fallback when a color fails to resolve — while the
foreground resolved correctly. Asymmetric failure, hence near-black on black.
Workaround (confirmed): Settings → Settings Editor → Terminal → Theme, set
to
any explicit value instead of inherit. Fixes it completely.
Suggested fix: ship an explicit default terminal theme in the image rather
than
relying on inherit.
Unresolved: the cold-start correlation and the mid-session flipping aren’t
explained by a single mechanism. Not yet tested in Chrome or Firefox — worth
checking whether this is Safari-specific CSS custom property resolution.
Thanks for posting that @jkrick. This sounds similar to a couple of known bugs where Safari displays blank pages. If you run into the problem (or similar) again, we recommend trying a different browser. We’ll continue exploring whether we can do something on our end (including the theme settings you describe) to help.