diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9ea9467d9b4c9..a3bf971f60ec0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@
 <a name="breaking_changes_1.15.0">[Breaking Changes:](#breaking_changes_1.15.0)</a>
 
 - [editor-preview] `EditorPreviewWidget` now extends `EditorWidget` and `EditorPreviewManager` extends and overrides `EditorManager`. `instanceof` checks can no longer distinguish between preview and non-preview editors; use `.isPreview` field instead. [#9518](https://github.com/eclipse-theia/theia/pull/9517)
+- [core] `outline-view-tree.ts` has been renamed to `outline-view-tree-model.ts` to match class name. [#9583](https://github.com/eclipse-theia/theia/pull/9583)
 
 ## v1.14.0 - 5/27/2021
 
diff --git a/packages/core/src/browser/tree/tree-widget.tsx b/packages/core/src/browser/tree/tree-widget.tsx
index 085f2a9f6df73..892d73b5e826a 100644
--- a/packages/core/src/browser/tree/tree-widget.tsx
+++ b/packages/core/src/browser/tree/tree-widget.tsx
@@ -99,6 +99,12 @@ export interface TreeProps {
      * `true` if a tree widget contributes to the global selection. Defaults to `false`.
      */
     readonly globalSelection?: boolean;
+
+    /**
+     *  `true` if the tree widget supports expansion only when clicking the expansion toggle. Defaults to `false`.
+     */
+    readonly expandOnlyOnExpansionToggleClick?: boolean;
+
 }
 
 /**
@@ -531,7 +537,13 @@ export class TreeWidget extends ReactWidget implements StatefulWidget {
         const nodeId = event.currentTarget.getAttribute('data-node-id');
         if (nodeId) {
             const node = this.model.getNode(nodeId);
-            this.handleClickEvent(node, event);
+            if (node && this.props.expandOnlyOnExpansionToggleClick) {
+                if (this.isExpandable(node) && !this.hasShiftMask(event) && !this.hasCtrlCmdMask(event)) {
+                    this.model.toggleNodeExpansion(node);
+                }
+            } else {
+                this.handleClickEvent(node, event);
+            }
         }
         event.stopPropagation();
     }
@@ -557,7 +569,8 @@ export class TreeWidget extends ReactWidget implements StatefulWidget {
         return <div
             data-node-id={node.id}
             className={className}
-            onClick={this.toggle}>
+            onClick={this.toggle}
+            onDoubleClick={this.handleExpansionToggleDblClickEvent}>
         </div>;
     }
 
@@ -1123,9 +1136,9 @@ export class TreeWidget extends ReactWidget implements StatefulWidget {
      */
     protected handleClickEvent(node: TreeNode | undefined, event: React.MouseEvent<HTMLElement>): void {
         if (node) {
+            const shiftMask = this.hasShiftMask(event);
+            const ctrlCmdMask = this.hasCtrlCmdMask(event);
             if (!!this.props.multiSelect) {
-                const shiftMask = this.hasShiftMask(event);
-                const ctrlCmdMask = this.hasCtrlCmdMask(event);
                 if (SelectableTreeNode.is(node)) {
                     if (shiftMask) {
                         this.model.selectRange(node);
@@ -1135,14 +1148,13 @@ export class TreeWidget extends ReactWidget implements StatefulWidget {
                         this.model.selectNode(node);
                     }
                 }
-                if (this.isExpandable(node) && !shiftMask && !ctrlCmdMask) {
-                    this.model.toggleNodeExpansion(node);
-                }
             } else {
                 if (SelectableTreeNode.is(node)) {
                     this.model.selectNode(node);
                 }
-                if (this.isExpandable(node) && !this.hasCtrlCmdMask(event) && !this.hasShiftMask(event)) {
+            }
+            if (!this.props.expandOnlyOnExpansionToggleClick) {
+                if (this.isExpandable(node) && !shiftMask && !ctrlCmdMask) {
                     this.model.toggleNodeExpansion(node);
                 }
             }
@@ -1191,6 +1203,17 @@ export class TreeWidget extends ReactWidget implements StatefulWidget {
         event.preventDefault();
     }
 
+    /**
+     * Handle the double-click mouse event on the expansion toggle.
+     * @param event the double-click mouse event.
+     */
+    protected handleExpansionToggleDblClickEvent(event: React.MouseEvent<HTMLElement>): void {
+        if (this.props.expandOnlyOnExpansionToggleClick) {
+            // Ignore the double-click event.
+            event.stopPropagation();
+        }
+    }
+
     /**
      * Convert the tree node to context menu arguments.
      * @param node the selectable tree node.
diff --git a/packages/outline-view/src/browser/outline-view-frontend-module.ts b/packages/outline-view/src/browser/outline-view-frontend-module.ts
index a8969c12f753b..a110da6fa61bc 100644
--- a/packages/outline-view/src/browser/outline-view-frontend-module.ts
+++ b/packages/outline-view/src/browser/outline-view-frontend-module.ts
@@ -34,7 +34,7 @@ import { OutlineViewWidgetFactory, OutlineViewWidget } from './outline-view-widg
 import '../../src/browser/styles/index.css';
 import { bindContributionProvider } from '@theia/core/lib/common/contribution-provider';
 import { OutlineDecoratorService, OutlineTreeDecorator } from './outline-decorator-service';
-import { OutlineViewTreeModel } from './outline-view-tree';
+import { OutlineViewTreeModel } from './outline-view-tree-model';
 
 export default new ContainerModule(bind => {
     bind(OutlineViewWidgetFactory).toFactory(ctx =>
@@ -61,7 +61,7 @@ export default new ContainerModule(bind => {
 function createOutlineViewWidget(parent: interfaces.Container): OutlineViewWidget {
     const child = createTreeContainer(parent);
 
-    child.rebind(TreeProps).toConstantValue({ ...defaultTreeProps, search: true });
+    child.rebind(TreeProps).toConstantValue({ ...defaultTreeProps, expandOnlyOnExpansionToggleClick: true, search: true });
 
     child.unbind(TreeWidget);
     child.bind(OutlineViewWidget).toSelf();
diff --git a/packages/outline-view/src/browser/outline-view-tree.ts b/packages/outline-view/src/browser/outline-view-tree-model.ts
similarity index 77%
rename from packages/outline-view/src/browser/outline-view-tree.ts
rename to packages/outline-view/src/browser/outline-view-tree-model.ts
index d75dd4ad8c2a6..759d92ed5f7f7 100644
--- a/packages/outline-view/src/browser/outline-view-tree.ts
+++ b/packages/outline-view/src/browser/outline-view-tree-model.ts
@@ -15,7 +15,7 @@
  ********************************************************************************/
 
 import { injectable, inject } from '@theia/core/shared/inversify';
-import { CompositeTreeNode, TreeModelImpl, TreeExpansionService, ExpandableTreeNode } from '@theia/core/lib/browser';
+import { CompositeTreeNode, TreeModelImpl, TreeExpansionService, ExpandableTreeNode, TreeNode } from '@theia/core/lib/browser';
 
 @injectable()
 export class OutlineViewTreeModel extends TreeModelImpl {
@@ -39,4 +39,16 @@ export class OutlineViewTreeModel extends TreeModelImpl {
         }
         return false;
     }
+
+    /**
+     * The default behavior of `openNode` calls `doOpenNode` which by default
+     * toggles the expansion of the node. Overriding to prevent expansion, but
+     * allow for the `onOpenNode` event to still fire on a double-click event.
+     */
+    openNode(raw?: TreeNode | undefined): void {
+        const node = raw || this.selectedNodes[0];
+        if (node) {
+            this.onOpenNodeEmitter.fire(node);
+        }
+    }
 }
diff --git a/packages/outline-view/src/browser/outline-view-widget.tsx b/packages/outline-view/src/browser/outline-view-widget.tsx
index 12ac92459eb86..b2a897b564759 100644
--- a/packages/outline-view/src/browser/outline-view-widget.tsx
+++ b/packages/outline-view/src/browser/outline-view-widget.tsx
@@ -25,7 +25,7 @@ import {
     TreeModel,
     ExpandableTreeNode
 } from '@theia/core/lib/browser';
-import { OutlineViewTreeModel } from './outline-view-tree';
+import { OutlineViewTreeModel } from './outline-view-tree-model';
 import { Message } from '@theia/core/shared/@phosphor/messaging';
 import { Emitter } from '@theia/core';
 import { CompositeTreeNode } from '@theia/core/lib/browser';