fixes #6797

src/vs/workbench/parts/files/browser/media/explorerviewlet.css

@@ -52,7 +52,7 @@
 
 .explorer-viewlet .explorer-open-editors .monaco-tree .monaco-tree-row > .content > .open-editor {
 	flex: 1;
-	margin-left: 4px;
+	margin-left: 1px;
 }
 
 .explorer-viewlet .explorer-open-editors .monaco-tree .monaco-tree-row > .content > .editor-group {
@@ -115,7 +115,7 @@
 }
 
 .explorer-viewlet .explorer-open-editors .monaco-tree .monaco-tree-row > .content > .open-editor.preview {
-	margin-left: 3px; /* accomodate for 1px padding */
+	margin-left: 0px; /* accomodate for 1px padding */
 }
 
 /* Theming */

src/vs/workbench/parts/files/browser/views/explorerView.ts

@@ -344,9 +344,9 @@ export class ExplorerView extends CollapsibleViewletView {
 			dnd: dnd,
 			accessibilityProvider: accessibility
 		}, {
-				autoExpandSingleChildren: true,
-				ariaLabel: nls.localize('treeAriaLabel', "Files Explorer")
-			});
+			autoExpandSingleChildren: true,
+			ariaLabel: nls.localize('treeAriaLabel', "Files Explorer")
+		});
 
 		this.toDispose.push(lifecycle.toDisposable(() => renderer.dispose()));