diff --git a/src/vs/base/browser/ui/tree/compressedObjectTreeModel.ts b/src/vs/base/browser/ui/tree/compressedObjectTreeModel.ts
index 72b148fe4a8..40990c89426 100644
--- a/src/vs/base/browser/ui/tree/compressedObjectTreeModel.ts
+++ b/src/vs/base/browser/ui/tree/compressedObjectTreeModel.ts
@@ -14,8 +14,15 @@ export interface ICompressedTreeElement<T> extends ITreeElement<T> {
 	readonly incompressible?: boolean;
 }
 
-export function compress<T>(element: ICompressedTreeElement<T>): ITreeElement<T[]> {
-	const result = [element.element];
+export interface ICompressedTreeNode<T> {
+	readonly elements: T[];
+	readonly incompressible: boolean;
+}
+
+export function compress<T>(element: ICompressedTreeElement<T>): ITreeElement<ICompressedTreeNode<T>> {
+	const elements = [element.element];
+	const incompressible = element.incompressible || false;
+
 	let childrenIterator: Iterator<ITreeElement<T>>;
 	let children: ITreeElement<T>[];
 
@@ -33,16 +40,16 @@ export function compress<T>(element: ICompressedTreeElement<T>): ITreeElement<T[
 			break;
 		}
 
-		result.push(element.element);
+		elements.push(element.element);
 	}
 
 	return {
-		element: result,
+		element: { elements, incompressible },
 		children: Iterator.map(Iterator.concat(Iterator.fromArray(children), childrenIterator), compress)
 	};
 }
 
-export function decompress<T>(element: ITreeElement<T>): ITreeElement<T[]> {
+export function decompress<T>(element: ITreeElement<ICompressedTreeNode<T>>): ITreeElement<T> {
 	throw new Error('todo');
 }
 
diff --git a/src/vs/base/test/browser/ui/tree/compressedObjectTreeModel.test.ts b/src/vs/base/test/browser/ui/tree/compressedObjectTreeModel.test.ts
index 7d5c5113292..6ff3bb1ee0a 100644
--- a/src/vs/base/test/browser/ui/tree/compressedObjectTreeModel.test.ts
+++ b/src/vs/base/test/browser/ui/tree/compressedObjectTreeModel.test.ts
@@ -5,7 +5,7 @@
 
 import * as assert from 'assert';
 import { ITreeElement } from 'vs/base/browser/ui/tree/tree';
-import { compress, ICompressedTreeElement } from 'vs/base/browser/ui/tree/compressedObjectTreeModel';
+import { compress, ICompressedTreeElement, ICompressedTreeNode } from 'vs/base/browser/ui/tree/compressedObjectTreeModel';
 import { Iterator } from 'vs/base/common/iterator';
 
 interface IResolvedTreeElement<T> extends ITreeElement<T> {
@@ -30,7 +30,9 @@ suite('CompressedObjectTreeModel', function () {
 
 		test('small', function () {
 			const actual: ICompressedTreeElement<number> = { element: 1 };
-			const expected: IResolvedTreeElement<number[]> = { element: [1] };
+			const expected: IResolvedTreeElement<ICompressedTreeNode<number>> =
+				{ element: { elements: [1], incompressible: false } };
+
 			assert.deepEqual(resolve(compress(actual)), expected);
 		});
 
@@ -43,11 +45,12 @@ suite('CompressedObjectTreeModel', function () {
 				]
 			};
 
-			const expected: IResolvedTreeElement<number[]> = {
-				element: [1], children: [
-					{ element: [11] },
-					{ element: [12] },
-					{ element: [13] }
+			const expected: IResolvedTreeElement<ICompressedTreeNode<number>> = {
+				element: { elements: [1], incompressible: false },
+				children: [
+					{ element: { elements: [11], incompressible: false } },
+					{ element: { elements: [12], incompressible: false } },
+					{ element: { elements: [13], incompressible: false } }
 				]
 			};
 
@@ -69,8 +72,8 @@ suite('CompressedObjectTreeModel', function () {
 				]
 			};
 
-			const expected: IResolvedTreeElement<number[]> = {
-				element: [1, 11, 111, 1111]
+			const expected: IResolvedTreeElement<ICompressedTreeNode<number>> = {
+				element: { elements: [1, 11, 111, 1111], incompressible: false }
 			};
 
 			assert.deepEqual(resolve(compress(actual)), expected);
@@ -94,12 +97,13 @@ suite('CompressedObjectTreeModel', function () {
 				]
 			};
 
-			const expected: IResolvedTreeElement<number[]> = {
-				element: [1, 11, 111], children: [
-					{ element: [1111] },
-					{ element: [1112] },
-					{ element: [1113] },
-					{ element: [1114] },
+			const expected: IResolvedTreeElement<ICompressedTreeNode<number>> = {
+				element: { elements: [1, 11, 111], incompressible: false },
+				children: [
+					{ element: { elements: [1111], incompressible: false } },
+					{ element: { elements: [1112], incompressible: false } },
+					{ element: { elements: [1113], incompressible: false } },
+					{ element: { elements: [1114], incompressible: false } },
 				]
 			};
 
@@ -132,18 +136,21 @@ suite('CompressedObjectTreeModel', function () {
 				]
 			};
 
-			const expected: IResolvedTreeElement<number[]> = {
-				element: [1], children: [
+			const expected: IResolvedTreeElement<ICompressedTreeNode<number>> = {
+				element: { elements: [1], incompressible: false },
+				children: [
 					{
-						element: [11, 111], children: [
-							{ element: [1112] },
-							{ element: [1113] },
+						element: { elements: [11, 111], incompressible: false },
+						children: [
+							{ element: { elements: [1112], incompressible: false } },
+							{ element: { elements: [1113], incompressible: false } },
 						]
 					},
 					{
-						element: [12, 121], children: [
-							{ element: [1212] },
-							{ element: [1213] },
+						element: { elements: [12, 121], incompressible: false },
+						children: [
+							{ element: { elements: [1212], incompressible: false } },
+							{ element: { elements: [1213], incompressible: false } },
 						]
 					}
 				]
@@ -167,9 +174,10 @@ suite('CompressedObjectTreeModel', function () {
 				]
 			};
 
-			const expected: IResolvedTreeElement<number[]> = {
-				element: [1, 11, 111], children: [
-					{ element: [1111] }
+			const expected: IResolvedTreeElement<ICompressedTreeNode<number>> = {
+				element: { elements: [1, 11, 111], incompressible: false },
+				children: [
+					{ element: { elements: [1111], incompressible: true } }
 				]
 			};
 
@@ -191,9 +199,10 @@ suite('CompressedObjectTreeModel', function () {
 				]
 			};
 
-			const expected: IResolvedTreeElement<number[]> = {
-				element: [1, 11], children: [
-					{ element: [111, 1111] }
+			const expected: IResolvedTreeElement<ICompressedTreeNode<number>> = {
+				element: { elements: [1, 11], incompressible: false },
+				children: [
+					{ element: { elements: [111, 1111], incompressible: true } }
 				]
 			};
 
@@ -215,11 +224,13 @@ suite('CompressedObjectTreeModel', function () {
 				]
 			};
 
-			const expected: IResolvedTreeElement<number[]> = {
-				element: [1, 11], children: [
+			const expected: IResolvedTreeElement<ICompressedTreeNode<number>> = {
+				element: { elements: [1, 11], incompressible: false },
+				children: [
 					{
-						element: [111], children: [
-							{ element: [1111] }
+						element: { elements: [111], incompressible: true },
+						children: [
+							{ element: { elements: [1111], incompressible: true } }
 						]
 					}
 				]
@@ -243,13 +254,16 @@ suite('CompressedObjectTreeModel', function () {
 				]
 			};
 
-			const expected: IResolvedTreeElement<number[]> = {
-				element: [1], children: [
+			const expected: IResolvedTreeElement<ICompressedTreeNode<number>> = {
+				element: { elements: [1], incompressible: false },
+				children: [
 					{
-						element: [11], children: [
+						element: { elements: [11], incompressible: true },
+						children: [
 							{
-								element: [111], children: [
-									{ element: [1111] }
+								element: { elements: [111], incompressible: true },
+								children: [
+									{ element: { elements: [1111], incompressible: true } }
 								]
 							}
 						]