diff --git a/svelte-app/src/lib/canvas/interactions.ts b/svelte-app/src/lib/canvas/interactions.ts
index e24fb5a..a926ba5 100644
--- a/svelte-app/src/lib/canvas/interactions.ts
+++ b/svelte-app/src/lib/canvas/interactions.ts
@@ -552,8 +552,9 @@ function onMousemove(e: MouseEvent) {
     const sym = layout.symbols.find(s => s.id === dragState!.placedId);
     if (!sym) return;
     const pos = screenToCanvas(e.clientX, e.clientY);
-    const dx = pos.x - dragState.startX!;
+    let dx = pos.x - dragState.startX!;
     const dy = pos.y - dragState.startY!;
+    if (sym.mirrored) dx = -dx;
     resizeSpur(sym, dx, dy, dragState.type === 'resize-spur-top', e.ctrlKey);
     layout.markDirty();
   }
@@ -562,9 +563,14 @@ function onMousemove(e: MouseEvent) {
     const sym = layout.symbols.find(s => s.id === dragState!.placedId);
     if (!sym) return;
     const pos = screenToCanvas(e.clientX, e.clientY);
-    const dx = pos.x - dragState.startX!;
+    let dx = pos.x - dragState.startX!;
     const dy = pos.y - dragState.startY!;
-    const isRight = dragState.type === 'resize-right';
+    let isRight = dragState.type === 'resize-right';
+    // When mirrored, swap handle direction and invert horizontal delta
+    if (sym.mirrored) {
+      dx = -dx;
+      isRight = !isRight;
+    }
 
     if (isCurvedType(sym.symbolId)) {
       resizeCurved(sym, dx, dy, isRight, e.ctrlKey);