diff --git a/A00_Common/spreadsheet/spreadsheet_grid.ts b/A00_Common/spreadsheet/spreadsheet_grid.ts
index 4963d5b3..9aec9cba 100644
--- a/A00_Common/spreadsheet/spreadsheet_grid.ts
+++ b/A00_Common/spreadsheet/spreadsheet_grid.ts
@@ -576,6 +576,20 @@ export function createGrid(ctx: SpreadsheetContext): GridHandle {
     return { x, y, w: box.w, h: box.h };
   }
 
+  /** `overlay` 안 자리 — `overlay` 자신이 이미 머리 칸(headColW·headRowH)만큼 밀려 있어
+   * `screenBoxOf`(격자 뿌리 기준)를 그대로 쓰면 머리 칸만큼 두 번 밀림(찾은 버그 · 2026-09-27). */
+  function overlayBoxOf(r: number, c: number): CellBox {
+    const box = boxOf(r, c);
+    const inFrozenCol = c < frozenCols;
+    const inFrozenRow = r < frozenRows;
+    return {
+      x: inFrozenCol ? box.x : box.x - paneBR.scrollLeft,
+      y: inFrozenRow ? box.y : box.y - paneBR.scrollTop,
+      w: box.w,
+      h: box.h,
+    };
+  }
+
   function renderSelection(): void {
     let selLayer = overlay.querySelector<HTMLElement>(".aislo-grid__sel-layer");
     if (!selLayer) {
@@ -596,8 +610,8 @@ export function createGrid(ctx: SpreadsheetContext): GridHandle {
       const inFrozenCol = range.c0 < frozenCols;
       const inFrozenRow = range.r0 < frozenRows;
       const screen: CellBox = {
-        x: headColW() + (inFrozenCol ? box.x : box.x - paneBR.scrollLeft),
-        y: headRowH() + (inFrozenRow ? box.y : box.y - paneBR.scrollTop),
+        x: inFrozenCol ? box.x : box.x - paneBR.scrollLeft,
+        y: inFrozenRow ? box.y : box.y - paneBR.scrollTop,
         w: box.w,
         h: box.h,
       };
@@ -611,13 +625,11 @@ export function createGrid(ctx: SpreadsheetContext): GridHandle {
       node.style.borderWidth = i === 0 ? "2px" : "1px";
       selLayer!.append(node);
     }
-    const active = boxOf(sel.활성.r, sel.활성.c);
-    const inFrozenCol = sel.활성.c < frozenCols;
-    const inFrozenRow = sel.활성.r < frozenRows;
+    const active = overlayBoxOf(sel.활성.r, sel.활성.c);
     const handle = document.createElement("div");
     handle.className = "aislo-grid__fill-handle";
-    handle.style.left = `${headColW() + (inFrozenCol ? active.x : active.x - paneBR.scrollLeft) + active.w - 4}px`;
-    handle.style.top = `${headRowH() + (inFrozenRow ? active.y : active.y - paneBR.scrollTop) + active.h - 4}px`;
+    handle.style.left = `${active.x + active.w - 4}px`;
+    handle.style.top = `${active.y + active.h - 4}px`;
     selLayer!.append(handle);
   }
 
@@ -643,8 +655,8 @@ export function createGrid(ctx: SpreadsheetContext): GridHandle {
       const inFrozenRow = ref.범위.r0 < frozenRows;
       const node = document.createElement("div");
       node.className = "aislo-grid__ref-highlight";
-      node.style.left = `${headColW() + (inFrozenCol ? merged.x : merged.x - paneBR.scrollLeft)}px`;
-      node.style.top = `${headRowH() + (inFrozenRow ? merged.y : merged.y - paneBR.scrollTop)}px`;
+      node.style.left = `${inFrozenCol ? merged.x : merged.x - paneBR.scrollLeft}px`;
+      node.style.top = `${inFrozenRow ? merged.y : merged.y - paneBR.scrollTop}px`;
       node.style.width = `${merged.w}px`;
       node.style.height = `${merged.h}px`;
       node.style.borderColor = REF_COLORS[ref.색번호 % REF_COLORS.length];