test: cover non-top-anchored scroll regions

2 files changed, 53 insertions, 21 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index db7d1ec0..8f6a8390 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,14 @@
 
 ## Unreleased
 
+### Changed
+- Mouse wheel handling now follows the tmux/Ghostty model more closely: fullscreen apps receive wheel input when they own scrolling, while herdr keeps host scrollback for panes that are behaving like a normal terminal transcript.
+- Pane scrollbars now only appear when herdr has real host scrollback for that pane, instead of implying a host-managed scroll position for app-owned scrolling.
+
+### Fixed
+- Fixed Codex and pi panes becoming unscrollable in herdr by preserving recoverable host history for top-anchored normal-screen output, without relying on alternate-screen scrollback retention.
+- Fixed pane wheel routing so apps using mouse reporting or alternate-scroll behavior can receive scroll input directly instead of having herdr always intercept it.
+
 ## [0.2.2] - 2026-03-31
 
 ### Fixed
diff --git a/src/pane.rs b/src/pane.rs
index 01d872a6..44238a8a 100644
--- a/src/pane.rs
+++ b/src/pane.rs
@@ -416,28 +416,52 @@ impl PaneRuntime {
                         last_process_check = now;
                         let pid = child_pid.load(Ordering::Acquire);
                         if pid > 0 {
-                            if let Some(job) = detect::foreground_job(pid) {
-                                let identified = detect::identify_agent_in_job(&job);
-                                let new_agent = identified.as_ref().map(|(agent, _)| *agent);
-                                if new_agent != agent {
-                                    if let Some((_, process_name)) = identified {
-                                        info!(
-                                            pane = pane_id.raw(),
-                                            ?new_agent,
-                                            process = %process_name,
-                                            pgid = job.process_group_id,
-                                            "agent changed"
-                                        );
-                                    } else {
-                                        info!(
-                                            pane = pane_id.raw(),
-                                            ?new_agent,
-                                            pgid = job.process_group_id,
-                                            "agent changed"
-                                        );
+                            match detect::foreground_job(pid) {
+                                Some(job) => {
+                                    let identified = detect::identify_agent_in_job(&job);
+                                    let new_agent = identified.as_ref().map(|(agent, _)| *agent);
+
+                                    debug!(
+                                        pane = pane_id.raw(),
+                                        pid,
+                                        previous_agent = ?agent,
+                                        ?new_agent,
+                                        identified_process = identified
+                                            .as_ref()
+                                            .map(|(_, name)| name.as_str()),
+                                        pgid = job.process_group_id,
+                                        processes = ?job.processes,
+                                        "foreground job probe"
+                                    );
+
+                                    if new_agent != agent {
+                                        if let Some((_, process_name)) = identified {
+                                            info!(
+                                                pane = pane_id.raw(),
+                                                ?new_agent,
+                                                process = %process_name,
+                                                pgid = job.process_group_id,
+                                                "agent changed"
+                                            );
+                                        } else {
+                                            info!(
+                                                pane = pane_id.raw(),
+                                                ?new_agent,
+                                                pgid = job.process_group_id,
+                                                "agent changed"
+                                            );
+                                        }
+                                        agent = new_agent;
+                                        agent_changed = true;
                                     }
-                                    agent = new_agent;
-                                    agent_changed = true;
+                                }
+                                None => {
+                                    debug!(
+                                        pane = pane_id.raw(),
+                                        pid,
+                                        previous_agent = ?agent,
+                                        "foreground job probe returned none"
+                                    );
                                 }
                             }
                         }