Resizing side panel causes composer to render outside of viewport (Flexbox/overflow issue)
What version of the Codex App are you using (From “About Codex” dialog)?
26.422.30944
What subscription do you have?
Plus
What platform is your computer?
Microsoft Windows NT 10.0.26200.0 x64
What issue are you seeing?
Hey OpenAI team!
In the Codex app, I found a CSS-related bug relating to the resizeable panels/handles during the planning flow.
During the planning interaction (confirmation step before executing a plan) resizing/shrinking an expanded side panel causes overflowing text in the "2. No, and tell Codex what to do differently" input field to stretch past the viewport.
If I type new instructions, e.g., adding new instructions in instead of pressing "1. Yes, execute this plan," that spans past the size of the viewport, resizing the side panel causes the text inside the agent chat to render outside of the bounds of the visible screen.
What steps can reproduce the bug?
1) Make the side panel larger than the left-hand conversation (e.g., I had the browser view open for Playwright/Browser Use plugin stuff)
2) Use planning mode, get to the user interaction before executing a plan
3) Type overflowing text in the "2. No, and tell Codex what to do differently" input field
4) Resize the viewport of the side panel
5) Watch the text fly outside of the visible viewport of the chat
<img width="4000" height="1486" alt="Image" src="https://github.com/user-attachments/assets/75d99a0c-5d98-4795-9f51-dbb4529ab960" />
What is the expected behavior?
The text should stay visually contained inside the "No, and tell Codex what to do differently" and shouldn't push the top anchor outside of the viewport.
Additional information
Specifically only happens in the planning input field and only when the text overflows in a small left panel width.
See below: smaller edge case that doesn't cause overflow but leaves empty space and shifts top alignment. It's some .composer or min-height issue.
<img width="1917" height="795" alt="Image" src="https://github.com/user-attachments/assets/5909f339-49f7-41c7-8d00-1fa4756b5914" />
Per Codex: "The planning confirmation panel appears to have a nested flex-column layout where the scrollable content/composer region is not constrained with min-height: 0 and overflow: auto/hidden. Long text causes the content region to preserve intrinsic height during resize. The fix is likely to make the modal body the only scroll container and ensure intermediate flex children have min-height: 0 / min-width: 0."