fix(tui/scrollback): keep last line visible in 1-row view

code-rs/tui/src/chatwidget.rs

@@ -37956,7 +37956,18 @@ impl WidgetRef for &ChatWidget<'_> {
                         p.record_render((idx, content_width), label.as_str(), ns);
                     }
                 }
+                let cell_start = acc;
                 acc = acc.saturating_add(line_count);
+                let cell_end = acc;
+
+                if cell
+                    .as_any()
+                    .is::<crate::history_cell::AssistantMarkdownCell>()
+                    && line_count >= 2
+                {
+                    spacing_ranges.push((cell_start, cell_start.saturating_add(1)));
+                    spacing_ranges.push((cell_end.saturating_sub(1), cell_end));
+                }
 
                 let mut should_add_spacing = idx < cells.len().saturating_sub(1) && line_count > 0;
                 if should_add_spacing {
@@ -38126,9 +38137,14 @@ impl WidgetRef for &ChatWidget<'_> {
                 scroll_from_top = scroll_from_top.saturating_sub(overscan_extra);
             }
 
-            // NOTE: when pinned to the bottom, we intentionally do not try to skip
-            // potential trailing padding rows inside cells. Doing so is brittle and
-            // can hide the last visible content line in very small viewports.
+            if clamped_scroll_offset == 0 && content_area.height == 1 {
+                scroll_from_top = self
+                    .history_render
+                    .adjust_scroll_to_content(scroll_from_top);
+            }
+
+            // NOTE: when pinned to the bottom, avoid guessing at cell-internal padding.
+            // Only skip known spacer intervals recorded by the history render cache.
 
             tracing::debug!(
                 target: "code_tui::scrollback",

code-rs/tui/tests/history_cutoff_probe.rs

@@ -129,10 +129,14 @@ fn collapsed_reasoning_before_exec_keeps_last_line() {
     harness.send_key(KeyEvent::new(KeyCode::Char('r'), KeyModifiers::CONTROL));
 
     let mut seq = 0_u64;
-    let order = |seq: &mut u64| OrderMeta {
-        request_ordinal: 42,
-        output_index: Some(0),
-        sequence_number: Some(*seq),
+    let order = |seq: &mut u64| {
+        let order = OrderMeta {
+            request_ordinal: 42,
+            output_index: Some(0),
+            sequence_number: Some(*seq),
+        };
+        *seq += 1;
+        order
     };
     let call_id = "exec-cutoff-collapsed".to_string();
     let cwd = PathBuf::from("/workspace");
@@ -359,10 +363,14 @@ fn exec_history_small_viewport_keeps_last_line() {
     harness.push_user_prompt("Run an exec command with verbose output.");
 
     let mut seq = 0_u64;
-    let order = |seq: &mut u64| OrderMeta {
-        request_ordinal: 3,
-        output_index: Some(0),
-        sequence_number: Some(*seq),
+    let order = |seq: &mut u64| {
+        let order = OrderMeta {
+            request_ordinal: 3,
+            output_index: Some(0),
+            sequence_number: Some(*seq),
+        };
+        *seq += 1;
+        order
     };
     let call_id = "exec-cutoff".to_string();
     let cwd = PathBuf::from("/workspace");