1 files changed, 30 insertions, 22 deletions

diff --git a/alacritty_terminal/src/grid/mod.rs b/alacritty_terminal/src/grid/mod.rs
index 8fdde0a4..59769883 100644
--- a/alacritty_terminal/src/grid/mod.rs
+++ b/alacritty_terminal/src/grid/mod.rs
@@ -268,33 +268,41 @@ impl<T: GridCell + Default + PartialEq + Clone> Grid<T> {
             self.display_offset = min(self.display_offset + positions, self.max_scroll_limit);
         }
 
-        // Create scrollback for the new lines.
-        self.increase_scroll_limit(positions);
+        // Only rotate the entire history if the active region starts at the top.
+        if region.start == 0 {
+            // Create scrollback for the new lines.
+            self.increase_scroll_limit(positions);
 
-        // Swap the lines fixed at the top to their target positions after rotation.
-        //
-        // Since we've made sure that the rotation will never rotate away the entire region, we
-        // know that the position of the fixed lines before the rotation must already be
-        // visible.
-        //
-        // We need to start from the bottom, to make sure the fixed lines aren't swapped with each
-        // other.
-        for i in (0..region.start.0).rev().map(Line::from) {
-            self.raw.swap(i, i + positions);
-        }
+            // Swap the lines fixed at the top to their target positions after rotation.
+            //
+            // Since we've made sure that the rotation will never rotate away the entire region, we
+            // know that the position of the fixed lines before the rotation must already be
+            // visible.
+            //
+            // We need to start from the bottom, to make sure the fixed lines aren't swapped with
+            // each other.
+            for i in (0..region.start.0).rev().map(Line::from) {
+                self.raw.swap(i, i + positions);
+            }
 
-        // Rotate the entire line buffer upward.
-        self.raw.rotate(-(positions as isize));
+            // Rotate the entire line buffer upward.
+            self.raw.rotate(-(positions as isize));
 
-        // Ensure all new lines are fully cleared.
-        let screen_lines = self.screen_lines();
-        for i in ((screen_lines - positions)..screen_lines).map(Line::from) {
-            self.raw[i].reset(&self.cursor.template);
+            // Swap the fixed lines at the bottom back into position.
+            let screen_lines = self.screen_lines() as i32;
+            for i in (region.end.0..screen_lines).rev().map(Line::from) {
+                self.raw.swap(i, i - positions);
+            }
+        } else {
+            // Rotate lines without moving anything into history.
+            for i in (region.start.0..region.end.0 - positions as i32).map(Line::from) {
+                self.raw.swap(i, i + positions);
+            }
         }
 
-        // Swap the fixed lines at the bottom back into position.
-        for i in (region.end.0..(screen_lines as i32)).rev().map(Line::from) {
-            self.raw.swap(i, i - positions);
+        // Ensure all new lines are fully cleared.
+        for i in (region.end.0 - positions as i32..region.end.0).map(Line::from) {
+            self.raw[i].reset(&self.cursor.template);
         }
     }