Terminal surface goes blank after task completes until workspace switch

[zach841]

Description

After a Claude Code task completes in a workspace, the terminal surface clears/goes blank. The content does not reappear until I switch to a different workspace (or click another window) and then switch back. This happens consistently after every task completion.

This appears to be the same class of bug as #1789 (terminal surfaces go blank on workspace switch), which was closed but is still reproducing on v0.63.2 as noted by a commenter there.

Steps to Reproduce

1. Open cmux with a Claude Code session running in a workspace
2. Give Claude a task and let it run to completion
3. When the task finishes, the terminal pane goes blank — no content rendered
4. Switch to a different window/workspace, then switch back
5. Content reappears

Expected Behavior

Terminal surface should remain rendered after a task completes without requiring a focus round-trip.

Environment

• cmux: 0.63.2 (build 79, commit 179b16c)
• macOS: Darwin 25.2.0 (Tahoe)
• Architecture: arm64 (Apple Silicon)

Notes

• Same root cause as Terminal surfaces go blank when switching between workspaces #1789 — the Metal surface likely isn't receiving a display() call when the task completes and the terminal content updates
• The switch-away-and-back recovery matches the behavior described in Terminal surfaces go blank when switching between workspaces #1789's comments, suggesting the surface state is intact but the display pipeline is stalled
• Terminal surfaces go blank when switching between workspaces #1789 was closed with PR Fix #2347 terminal focus and surface recovery #2354, but the fix doesn't cover this trigger (task completion vs. workspace switch)

[serabi]

This is happening to me too, and it also happens when running Pi windows. Example screenshot:

I tried turning off alerts because that seemed to make it worse but that hasn't fixed the issue.

Environment

• cmux: 0.63.2 (build 79, commit 179b16ce6)
• macOS: Tahoe 26.4.1 (25E253)
• Architecture: arm64 (Apple Silicon - M5 chip)

[nhothi]

also facing the same issue with v0.63.2

Environment

• cmux: 0.63.2 (build 79, commit 179b16ce6)
• macOS: Sequoia 15.7.5 (24G624)
• Architecture: arm64 (Apple Silicon - M1 Max chip)

[zach841]

Bumping — two other users have confirmed reproducing this on 0.63.2 across M1 Max / M5 hardware on both Sequoia and Tahoe. Any chance a maintainer can take a look?