[Bug] question tool in opencode mini: options beyond viewport invisible + IME caret jumps in custom-answer input (macOS)

Description

Two UI bugs in the question tool in opencode mini:

1. Options beyond the viewport are invisible but selectable — when a question has more options than fit on screen, options below the viewport are not rendered, yet the arrow keys still move through them blindly.

2. IME caret issues in the "Type your own answer" field —

   • macOS default English IME: the caret jumps to the end of the text after every keystroke. Even after manually positioning the caret and typing again, it immediately jumps back to the end.
   • macOS default Chinese IME: after committing characters, the caret jumps to the middle of the text and the arrow keys stop working (only Cmd+Arrow keys work). This recurs on every input. When deleting, after removing 1–2 characters the caret is forced to the middle of the text, and further deletion is blocked until the caret has been moved.

Plugins

N/A

OpenCode version

1.18.15

Steps to reproduce

1. Run opencode --mini in Ghostty on macOS.
2. Ask the model to call the question tool with more options than fit on screen; the options below the viewport are invisible but still selectable.
3. Select "Type your own answer".
4. Type with the English layout: the caret jumps to the end after each letter.
5. Switch to the macOS built-in Chinese IME: after committing at least two Chinese characters the caret jumps to the middle; arrow keys no longer move the caret (Cmd+Arrow only). Repeat typing, then try deleting.
6. Expected: caret stays where placed and arrow keys work at all times.

Screenshot and/or share link

Please watch the content of the following link.
https://streamable.com/c9wpp7

Operating System

macOS 26.5.1

Terminal

Ghostty