diff --git a/apps/ai-game-creator-shell/src/features/project-workspace/ResourceReferenceInput.tsx b/apps/ai-game-creator-shell/src/features/project-workspace/ResourceReferenceInput.tsx
index bf0a53899..c4720aa77 100644
--- a/apps/ai-game-creator-shell/src/features/project-workspace/ResourceReferenceInput.tsx
+++ b/apps/ai-game-creator-shell/src/features/project-workspace/ResourceReferenceInput.tsx
@@ -493,6 +493,7 @@ function ResourceReferenceEditor({
           handleSelectMention(option, textNode, closeMenu)
         }
         menuRenderFn={renderMentionMenu}
+        anchorClassName="resource-reference-menu-anchor"
         preselectFirstItem
       />
       {pickerOpen && pickerPosition
diff --git a/apps/ai-game-creator-shell/src/styles.css b/apps/ai-game-creator-shell/src/styles.css
index 40b9bc2b5..bb08ea406 100644
--- a/apps/ai-game-creator-shell/src/styles.css
+++ b/apps/ai-game-creator-shell/src/styles.css
@@ -4540,22 +4540,30 @@ h2 {
 .resource-reference-menu {
   display: grid;
   gap: 2px;
-  min-width: 240px;
-  max-height: 260px;
+  width: min(360px, calc(100vw - 48px));
+  max-height: min(240px, calc(100vh - 140px));
   overflow: auto;
+  overscroll-behavior: contain;
   padding: 6px;
   border: 1px solid var(--platform-subpanel-border, #dbe3ef);
   border-radius: 12px;
   background: var(--platform-panel-fill, #fff);
   box-shadow: 0 12px 28px rgba(15, 23, 42, 0.16);
+  scrollbar-color: #cbd5e1 transparent;
+  scrollbar-width: thin;
+}
+
+.resource-reference-menu-anchor {
+  z-index: 90;
 }
 
 .resource-reference-menu button {
-  display: flex;
+  display: grid;
+  grid-template-columns: minmax(0, 1fr) auto;
   align-items: center;
-  justify-content: space-between;
   gap: 12px;
   width: 100%;
+  min-width: 0;
   padding: 8px 10px;
   border: 0;
   border-radius: 8px;
@@ -4570,8 +4578,20 @@ h2 {
   background: var(--platform-subpanel-fill, #f1f5f9);
 }
 
+.resource-reference-menu button > span {
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
 .resource-reference-menu small {
+  max-width: 132px;
+  overflow: hidden;
   color: var(--platform-muted-text, #64748b);
+  font-size: 11px;
+  text-overflow: ellipsis;
+  white-space: nowrap;
 }
 
 .resource-reference-picker {