Codex CLI in an Eclipse IDE terminal doesn't allow backward scrolling (also with --no-alt-screen option)

[stefano-1973]

Codex CLI in an Eclipse IDE terminal window doesn't allow backward scrolling. Also, running Codex with the --no-alt-screen option doesn't change anything.
I know the Eclipse terminal is scrollable and Codex CLI running in Windows cmd or powershell is scrollable.
So there must be some problem between Codex CLI and Eclipse terminal.

Steps to reproduce

• Open a terminal in eclipse IDE
• Start Codex CLI with or without --no-alt-screen (even setting "set TERM=dumb" before calling codex doesn't help)
• Give Codex the following prompt : write 50 rows (a enter b enter c etc...)
• Try scrolling backward and see if it appears

Tested under this environment:

• Windows Server 2019
• Eclipse IDE/Platform version Version: 2026-03 (4.39.0) Build id: 20260305-0817
• Codex Cli version 135

Workarounds

1. Use the internal Codex transcript directrly in the Eclipse terminal running Codex TUI, activable with Ctrl+T
2. fake codex to think it's running inside Zwellij:
   For linux:

ZELLIJ=1 codex --no-alt-screen -c tui.raw_output_mode=true

For windows:

set ZELLIJ=1
codex --no-alt-screen -c tui.raw_output_mode=true

[stefano-1973]

Because the cause is Codex Cli only when used with Eclipse terminal (and vice-versa), I open also this: openai/codex#25412

[merks]

I would have extremely low expectations with respect to someone else doing something to fix whatever problem there might be here. Whomever wants this to work will most likely need to invest the effort needed to do whatever is necessary to make it work themselves.

[vogella]

@stefano-1973 What does Codex CLI say about a fix in this repo?

[vogella]

eclipse-platform/eclipse.platform.swt#3350

[merks]

eclipse-platform/eclipse.platform.swt#3350

I guess you meant to link tab reordering to a different issue.

[stefano-1973]

The problem is present also if I start linux elipse in WSL2 ubuntu. Eclipse installed in wsl2 with "sudo snap install eclipse --classic"

[vogella]

@stefano-1973 I do not have the option to use Codex CLI (with --no-alt-screen).

Can you enable a trace option so that we can see which sequence is send?

To see what --no-alt-screen actually does, please capture a terminal trace:

1. Create a file named .options beside eclipse.exe with this one line:

org.eclipse.terminal.control/debug/log/char=true

2. Start Eclipse from that folder with -debug (it reads .options from the current directory):

eclipse.exe -debug

3. In the Eclipse terminal, run codex --no-alt-screen, print 50 rows (a, b, c, ...), and try scrolling back.

4. Attach the log from:

.metadata.plugins\org.eclipse.terminal.control\tmterminal.log

If it contains \x1b[?1049h, then --no-alt-screen did not take effect (also useful to know); if that sequence is absent, it's exactly the trace we need.

[stefano-1973]

Codex analisys

Even with --no-alt-screen, Codex is still a raw-mode TUI application and does not emit output as simple line-by-line stdout. It uses terminal control sequences to redraw and insert history into the normal screen buffer. Eclipse Terminal may not be recording those screen-buffer updates into scrollback the same way other terminals do.

So this could potentially be addressed either by:

• Codex adding a fallback/raw output mode for Eclipse Terminal, similar to the Zellij raw path; or
• Eclipse Terminal improving scrollback handling for raw-mode/fullscreen-style terminal applications that do not use the alternate screen buffer.

[vogella]

I have a patch ready which works for Claude CLI, only awaiting your input from the log.

[vogella]

Btw. I tried to suggest that you clone this repo and ask Codex to analyse what can be done in Eclipse to fix it. This is not necessary anymore as I already have a local patch.

Maybe once I have published my patch, you can ask Codex for feedback.