diff --git a/svelte-app/src/lib/canvas/interactions.ts b/svelte-app/src/lib/canvas/interactions.ts
index b0ba753..3264abb 100644
--- a/svelte-app/src/lib/canvas/interactions.ts
+++ b/svelte-app/src/lib/canvas/interactions.ts
@@ -490,6 +490,14 @@ function onMousemove(e: MouseEvent) {
       if (!pastDragThreshold(pos.x, pos.y, dragState.startX!, dragState.startY!, DRAG_THRESHOLD)) return;
       dragState.dragActivated = true;
     }
+    // Shift: constrain to orthogonal axis (horizontal or vertical)
+    if (e.shiftKey) {
+      if (Math.abs(pos.x - dragState.startX!) >= Math.abs(pos.y - dragState.startY!)) {
+        pos.y = dragState.startY!;
+      } else {
+        pos.x = dragState.startX!;
+      }
+    }
     const sym = layout.symbols.find(s => s.id === dragState!.placedId);
     if (!sym) return;
     const bb = getAABB(0, 0, sym.w, sym.h, sym.rotation);
@@ -508,6 +516,14 @@ function onMousemove(e: MouseEvent) {
       if (!pastDragThreshold(pos.x, pos.y, dragState.startX!, dragState.startY!, DRAG_THRESHOLD)) return;
       dragState.dragActivated = true;
     }
+    // Shift: constrain to orthogonal axis
+    if (e.shiftKey) {
+      if (Math.abs(pos.x - dragState.startX!) >= Math.abs(pos.y - dragState.startY!)) {
+        pos.y = dragState.startY!;
+      } else {
+        pos.x = dragState.startX!;
+      }
+    }
     for (const { id, offsetX, offsetY } of dragState.multiOffsets) {
       const sym = layout.symbols.find(s => s.id === id);
       if (!sym) continue;