diff --git a/apps/viewer/src/components/gm/GmWindow.vue b/apps/viewer/src/components/gm/GmWindow.vue
index c14f043..9fa106b 100644
--- a/apps/viewer/src/components/gm/GmWindow.vue
+++ b/apps/viewer/src/components/gm/GmWindow.vue
@@ -21,19 +21,12 @@ const emit = defineEmits<{
 const windowEl = ref<HTMLDivElement | null>(null);
 const x = ref(props.initialX);
 const y = ref(props.initialY);
-const w = ref(props.initialWidth);
-const h = ref(props.initialHeight);
 const isDragging = ref(false);
 let dragOffsetX = 0;
 let dragOffsetY = 0;
 
 function onTitleMouseDown(e: MouseEvent) {
   if ((e.target as HTMLElement).closest("button")) return;
-  // Snapshot current rendered size so resize isn't lost on drag
-  if (windowEl.value) {
-    w.value = windowEl.value.offsetWidth;
-    h.value = windowEl.value.offsetHeight;
-  }
   isDragging.value = true;
   dragOffsetX = e.clientX - x.value;
   dragOffsetY = e.clientY - y.value;
@@ -53,6 +46,12 @@ function onMouseUp() {
 onMounted(() => {
   window.addEventListener("mousemove", onMouseMove);
   window.addEventListener("mouseup", onMouseUp);
+  // Set initial size imperatively so Vue's reactive style binding never
+  // touches width/height — the browser's CSS resize handle owns them.
+  if (windowEl.value) {
+    windowEl.value.style.width = `${props.initialWidth}px`;
+    windowEl.value.style.height = `${props.initialHeight}px`;
+  }
 });
 
 onUnmounted(() => {
@@ -68,8 +67,6 @@ onUnmounted(() => {
     :style="{
       left: `${x}px`,
       top: `${y}px`,
-      width: `${w}px`,
-      height: `${h}px`,
       cursor: isDragging ? 'grabbing' : 'default',
       zIndex: 200,
     }"