less flicker when opening first editor

src/vs/workbench/browser/parts/editor/media/tabstitle.css

@@ -5,15 +5,15 @@
 
 /* Title Container */
 
-.vs .monaco-workbench > .part.editor > .content > .one-editor-silo > .container > .title.tabs {
+.vs .monaco-workbench > .part.editor > .content > .one-editor-silo > .container > .title.tabs.shows-tabs {
 	background: #F3F3F3;
 }
 
-.vs-dark .monaco-workbench > .part.editor > .content > .one-editor-silo > .container > .title.tabs {
+.vs-dark .monaco-workbench > .part.editor > .content > .one-editor-silo > .container > .title.tabs.shows-tabs {
 	background: #252526;
 }
 
-.hc-black .monaco-workbench > .part.editor > .content > .one-editor-silo > .container > .title.tabs {
+.hc-black .monaco-workbench > .part.editor > .content > .one-editor-silo > .container > .title.tabs.shows-tabs {
 	border-bottom: 1px solid #6FC3DF;
 }
 

src/vs/workbench/browser/parts/editor/tabsTitleControl.ts

@@ -320,6 +320,7 @@ export class TabsTitleControl extends TitleControl {
 
 		this.tabDisposeables = dispose(this.tabDisposeables);
 		this.editorLabels = dispose(this.editorLabels);
+		DOM.removeClass(this.titleContainer, 'shows-tabs');
 	}
 
 	private refreshTabs(group: IEditorGroup): void {
@@ -330,7 +331,8 @@ export class TabsTitleControl extends TitleControl {
 		const tabContainers: HTMLElement[] = [];
 
 		// Add a tab for each opened editor
-		this.context.getEditors().forEach(editor => {
+		const editors = this.context.getEditors();
+		editors.forEach(editor => {
 
 			// Tab Container
 			const tabContainer = document.createElement('div');
@@ -366,6 +368,10 @@ export class TabsTitleControl extends TitleControl {
 
 		// Add to tabs container
 		tabContainers.forEach(tab => this.tabsContainer.appendChild(tab));
+
+		if (editors.length > 0) {
+			DOM.addClass(this.titleContainer, 'shows-tabs');
+		}
 	}
 
 	public layout(): void {