diff --git a/crates/ui-egui/src/grid.rs b/crates/ui-egui/src/grid.rs
index ab434f7..316714c 100644
--- a/crates/ui-egui/src/grid.rs
+++ b/crates/ui-egui/src/grid.rs
@@ -2724,7 +2724,17 @@ pub fn point_move(app: &mut SheetApp, ed: &mut EditState, dr: i64, dc: i64, exte
     let from = ed.point_cell.unwrap_or(ed.cell);
     let to = from.offset_clamped(dr, dc);
     let text = if extend {
-        let anchor = ed.point.and_then(|(s, e)| ed.text.get(s..e)).and_then(|t| CellRef::parse(t.split(':').next().unwrap_or(""))).unwrap_or(from);
+        // The anchor is the corner opposite the moving end: the written range is normalized, so
+        // after extending up or left its first cell is the moving end, not the anchor.
+        let pointed = ed.point.and_then(|(s, e)| ed.text.get(s..e)).and_then(RangeRef::parse);
+        let anchor = pointed
+            .map(|r| {
+                CellRef::new(
+                    if from.row == r.start.row { r.end.row } else { r.start.row },
+                    if from.col == r.start.col { r.end.col } else { r.start.col },
+                )
+            })
+            .unwrap_or(from);
         RangeRef::new(anchor, to).a1()
     } else {
         to.a1()
diff --git a/crates/ui-egui/tests/interaction.rs b/crates/ui-egui/tests/interaction.rs
index f5d7d3e..058d68b 100644
--- a/crates/ui-egui/tests/interaction.rs
+++ b/crates/ui-egui/tests/interaction.rs
@@ -191,6 +191,25 @@ fn arrows_escape_and_undo() {
     assert_eq!(value(&h, "B2"), Value::Empty);
 }
 
+#[test]
+fn shift_arrows_in_point_mode_extend_from_the_pointed_cell() {
+    let mut s = blank();
+    s.execute("selection.set", json!({"cell": "A11"})).unwrap();
+    let mut h = harness(s);
+    text(&mut h, "=SUM(");
+    key(&mut h, Key::ArrowUp, Modifiers::NONE);
+    let edited = |h: &egui_kittest::Harness<'static, SheetApp>| h.state().editor.as_ref().map(|e| e.text.clone());
+    assert_eq!(edited(&h).as_deref(), Some("=SUM(A10"));
+    // Shift is held down, as on a real keyboard: the backend reports it before the arrow keys.
+    h.input_mut().events.push(Event::ModifiersChanged(Modifiers::SHIFT));
+    for expected in ["=SUM(A9:A10", "=SUM(A8:A10", "=SUM(A7:A10"] {
+        key(&mut h, Key::ArrowUp, Modifiers::SHIFT);
+        assert_eq!(edited(&h).as_deref(), Some(expected));
+    }
+    key(&mut h, Key::ArrowDown, Modifiers::SHIFT);
+    assert_eq!(edited(&h).as_deref(), Some("=SUM(A8:A10"), "Shift+Down shrinks back towards the anchor");
+}
+
 #[test]
 fn shortcuts_format_and_extend() {
     let mut s = blank();