diff --git a/src/vs/workbench/api/browser/mainThreadEditorTabs.ts b/src/vs/workbench/api/browser/mainThreadEditorTabs.ts
index f8683908975..5f90c8a7744 100644
--- a/src/vs/workbench/api/browser/mainThreadEditorTabs.ts
+++ b/src/vs/workbench/api/browser/mainThreadEditorTabs.ts
@@ -49,7 +49,7 @@ export class MainThreadEditorTabs {
 	private _buildTabObject(editor: EditorInput, group: IEditorGroup): IEditorTabDto {
 		// Even though the id isn't a diff / sideBySide on the main side we need to let the ext host know what type of editor it is
 		const editorId = editor.editorId;
-		const tabKind = editor instanceof DiffEditorInput ? TabKind.DIFF : editor instanceof SideBySideEditorInput ? TabKind.SIDEBYSIDE : TabKind.SINGULAR;
+		const tabKind = editor instanceof DiffEditorInput ? TabKind.Diff : editor instanceof SideBySideEditorInput ? TabKind.SidebySide : TabKind.Singular;
 		const tab: IEditorTabDto = {
 			viewColumn: editorGroupToColumn(this._editorGroupsService, group),
 			label: editor.getName(),
diff --git a/src/vs/workbench/api/common/extHost.protocol.ts b/src/vs/workbench/api/common/extHost.protocol.ts
index 91b1a26066f..0f88ecf65af 100644
--- a/src/vs/workbench/api/common/extHost.protocol.ts
+++ b/src/vs/workbench/api/common/extHost.protocol.ts
@@ -626,10 +626,10 @@ export interface IEditorTabGroupDto {
 }
 
 export enum TabKind {
-	SINGULAR = 0,
-	DIFF = 1,
-	SIDEBYSIDE = 2,
-	OTHER = 3
+	Singular = 0,
+	Diff = 1,
+	SidebySide = 2,
+	Other = 3
 }
 
 export interface IEditorTabDto {
diff --git a/src/vscode-dts/vscode.proposed.tabs.d.ts b/src/vscode-dts/vscode.proposed.tabs.d.ts
index 3f2ed50f451..41bac7b10a2 100644
--- a/src/vscode-dts/vscode.proposed.tabs.d.ts
+++ b/src/vscode-dts/vscode.proposed.tabs.d.ts
@@ -8,10 +8,10 @@ declare module 'vscode' {
 	// https://github.com/Microsoft/vscode/issues/15178
 
 	export enum TabKind {
-		SINGULAR = 0,
-		DIFF = 1,
-		SIDEBYSIDE = 2,
-		OTHER = 3
+		Singular = 0,
+		Diff = 1,
+		SidebySide = 2,
+		Other = 3
 	}
 
 	/**