diff --git a/packages/core/src/browser/shell/tab-bars.ts b/packages/core/src/browser/shell/tab-bars.ts
index 8a983897940ad..8e01b66d3dc83 100644
--- a/packages/core/src/browser/shell/tab-bars.ts
+++ b/packages/core/src/browser/shell/tab-bars.ts
@@ -1145,7 +1145,7 @@ export class SideTabBar extends ScrollableTabBar {
                 }
 
                 // Special handling if only one element is overflowing.
-                if (overflowStartIndex === n - 1) {
+                if (overflowStartIndex === n - 1 && renderData[overflowStartIndex]) {
                     if (!this.tabsOverflowData) {
                         overflowStartIndex--;
                         renderData[overflowStartIndex].visible = false;