[Bug]: iPad portrait: no way back to the parent after opening a sub-agent thread #36165

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. Open the native T3 Code iOS app on an iPad in portrait orientation.
2. Open a parent thread that has a sub-agent thread.
3. Tap the sub-agent thread link from inside the parent thread.
4. Try to return to the parent using a back button or back gesture.
5. For comparison, return to the parent via the sidebar, rotate to landscape, and open the same sub-agent thread again.

Expected behavior#

Opening a sub-agent thread should preserve an obvious way to return directly to its parent in either orientation, such as a back/close button or a working back gesture.

In landscape, the sub-agent opens in a full-page modal/dialog with an exit/back control that returns to the parent. Portrait should provide an equivalent return path.

Actual behavior#

In portrait, the sub-agent thread opens without a back button or a working gesture to return to the parent. I have to open the sidebar and select the parent thread manually.

This does not happen in landscape: the sub-agent opens in a full-page modal/dialog with a close control, which returns me to the parent.

Related: #23765, closed through #23795, describes Android Back navigation returning to the project list instead of the delegator. This report differs: on iPad in portrait there is no back control or gesture available at all. The related PR also notes that iOS was not tested on a device.

Impact#

Minor bug or occasional failure

Version or commit#

2.3.0 (reported in the native iOS app). Observed on 14 November 2026.

Environment#

iPad, native T3 Code iOS app. Reproduces in portrait; landscape provides a dismissible sub-agent modal/dialog. Exact iPad model and iPadOS version not recorded.

Logs or stack traces#

Screenshots, recordings, or supporting files#

ScreenRecording_11-14-2026 01-44-43_1.mp4

Workaround#

Open the sidebar and select the parent thread manually. Alternatively, return to the parent and open the sub-agent in landscape, where the modal/dialog has a close control.