--- a/devtools/client/framework/components/ToolboxTabs.js
+++ b/devtools/client/framework/components/ToolboxTabs.js
@@ -160,21 +160,22 @@ class ToolboxTabs extends Component {
         enabledTabs.includes(currentToolId)) {
       let selectedToolWidth = this._cachedToolTabsWidthMap.get(currentToolId);
       while ((sumWidth + selectedToolWidth) > toolboxWidth &&
              visibleTabs.length > 0) {
         let removingToolId  = visibleTabs.pop();
         let removingToolWidth = this._cachedToolTabsWidthMap.get(removingToolId);
         sumWidth -= removingToolWidth;
       }
-      visibleTabs.push(currentToolId);
-    }
 
-    if (visibleTabs.length === 0) {
-      visibleTabs = [enabledTabs[0]];
+      // If toolbox width is narrow, toolbox display only chevron menu.
+      // i.e. All tool tabs will overflow.
+      if ((sumWidth + selectedToolWidth) <= toolboxWidth) {
+        visibleTabs.push(currentToolId);
+      }
     }
 
     let willOverflowTabs = enabledTabs.filter(id => !visibleTabs.includes(id));
     if (!this.equalToolIdArray(this.state.overflowedTabIds, willOverflowTabs)) {
       this.setState({ overflowedTabIds: willOverflowTabs });
     }
   }