Android: code block copy button shows an empty square, no icon #17084

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/mobile

Steps to reproduce

1. On Android, open a thread where the agent replied with a fenced code block (for example a long ```text prompt).
2. Look at the code block header, top right.

Expected behavior

A visible copy icon. One tap copies the whole block. This matters most on a phone: long lines scroll sideways, and selecting the text by hand is not practical.

Actual behavior

The header shows an empty square where the copy button should be. No icon is visible, so the one-tap copy is hard to find. I could not confirm whether a tap on the blank square copies the text.

The button is CopyTextButton in MarkdownCodeBlock (apps/mobile/src/features/threads/ThreadFeed.tsx). On Android it draws content_copy -> IconCopy through AppSymbol, tinted with --color-icon-subtle. The tint or the icon may not render on Android.

Impact

Minor bug or occasional failure

Version or commit

Android app from Google Play (current as of 2026-10-08), connected to a desktop host

Environment

Android phone, dark theme, T3 Connect

Workaround

Long-press the message and copy all of it, then cut the extra text.