keyboard accessibility

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

@@ -35,6 +35,10 @@
 	padding-left: 10px;
 }
 
+.monaco-workbench > .part.editor > .content > .one-editor-container > .title .tabs-container > .tab:focus {
+	outline-offset: -2px;
+}
+
 .hc-black .monaco-workbench > .part.editor > .content > .one-editor-container > .title.active .tabs-container > .tab.active  {
 	border: 1px solid #6FC3DF;
 }
@@ -71,27 +75,37 @@
 /* Tab Close */
 
 .monaco-workbench > .part.editor > .content > .one-editor-container .title .tabs-container > .tab > .tab-close {
-	opacity: 0; /* hide the close button  by default */
+	margin-top: auto;
+	margin-bottom: auto;
+	width: 28px;
 }
 
-.monaco-workbench > .part.editor > .content > .one-editor-container .title.active .tabs-container > .tab.active > .tab-close,			/* always show it for active tab */
-.monaco-workbench > .part.editor > .content > .one-editor-container .title.active .tabs-container > .tab:hover > .tab-close,			/* always show it on hover */
-.monaco-workbench > .part.editor > .content > .one-editor-container .title.active .tabs-container > .tab.active:hover > .tab-close,	/* always show it on hover */
-.monaco-workbench > .part.editor > .content > .one-editor-container .title .tabs-container > .tab.dirty > .tab-close {				/* always show it for dirty tabs */
+.monaco-workbench > .part.editor > .content > .one-editor-container .title.active .tabs-container > .tab.active > .tab-close .action-label,				/* always show it for active tab */
+.monaco-workbench > .part.editor > .content > .one-editor-container .title.active .tabs-container > .tab > .tab-close .action-label:focus,				/* always show it on focus */
+.monaco-workbench > .part.editor > .content > .one-editor-container .title.active .tabs-container > .tab:hover > .tab-close .action-label,				/* always show it on hover */
+.monaco-workbench > .part.editor > .content > .one-editor-container .title.active .tabs-container > .tab.active:hover > .tab-close .action-label,		/* always show it on hover */
+.monaco-workbench > .part.editor > .content > .one-editor-container .title .tabs-container > .tab.dirty > .tab-close .action-label {					/* always show it for dirty tabs */
 	opacity: 1;
 }
 
-.monaco-workbench > .part.editor > .content > .one-editor-container .title .tabs-container > .tab.active > .tab-close,			/* show dimmed for inactive group */
-.monaco-workbench > .part.editor > .content > .one-editor-container .title .tabs-container > .tab.active:hover > .tab-close {		/* show dimmed for inactive group */
+.monaco-workbench > .part.editor > .content > .one-editor-container .title .tabs-container > .tab.active > .tab-close .action-label,					/* show dimmed for inactive group */
+.monaco-workbench > .part.editor > .content > .one-editor-container .title .tabs-container > .tab.active:hover > .tab-close .action-label {				/* show dimmed for inactive group */
 	opacity: 0.5;
 }
 
-.monaco-workbench > .part.editor > .content > .one-editor-container .title .tabs-container > .tab:hover > .tab-close {			/* show more dimmed for inactive group and tab */
+.monaco-workbench > .part.editor > .content > .one-editor-container .title .tabs-container > .tab:hover > .tab-close .action-label {					/* show more dimmed for inactive group and tab */
 	opacity: 0.4;
 }
 
 .monaco-workbench > .part.editor > .content > .one-editor-container .title .tabs-container > .tab > .tab-close .action-label {
-	width: 20px;
+	opacity: 0;
+	display: block;
+	height: 16px;
+	width: 16px;
+	background-size: 16px;
+	background-position: center center;
+	background-repeat: no-repeat;
+	margin-right: 0.5em;
 }
 
 .vs .monaco-workbench > .part.editor > .content > .one-editor-container > .title .tabs-container > .tab.dirty .close-editor-action {

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

@@ -48,8 +48,7 @@
 /* Title Actions */
 
 .monaco-workbench > .part.editor > .content > .one-editor-container > .title .title-actions .action-label,
-.monaco-workbench > .part.editor > .content > .one-editor-container > .title .group-actions .action-label,
-.monaco-workbench > .part.editor > .content > .one-editor-container .title .tabs-container > .tab > .tab-close .action-label {
+.monaco-workbench > .part.editor > .content > .one-editor-container > .title .group-actions .action-label {
 	display: block;
 	height: 35px;
 	width: 28px;

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

@@ -17,6 +17,8 @@ import {Builder, $} from 'vs/base/browser/builder';
 import {MIME_BINARY} from 'vs/base/common/mime';
 import {IEditorGroup, IEditorIdentifier, asFileEditorInput} from 'vs/workbench/common/editor';
 import {ToolBar} from 'vs/base/browser/ui/toolbar/toolbar';
+import {StandardKeyboardEvent} from 'vs/base/browser/keyboardEvent';
+import {CommonKeybindings} from 'vs/base/common/keyCodes';
 import {ActionBar, Separator} from 'vs/base/browser/ui/actionbar/actionbar';
 import {StandardMouseEvent} from 'vs/base/browser/mouseEvent';
 import {IWorkbenchEditorService} from 'vs/workbench/services/editor/common/editorService';
@@ -243,6 +245,7 @@ export class TabsTitleControl extends TitleControl {
 		this.context.getEditors().forEach(editor => {
 			const tabContainer = document.createElement('div');
 			tabContainer.draggable = true;
+			tabContainer.tabIndex = 0;
 			DOM.addClass(tabContainer, 'tab monaco-editor-background');
 			tabContainers.push(tabContainer);
 
@@ -326,6 +329,19 @@ export class TabsTitleControl extends TitleControl {
 			}
 		}));
 
+		// Open on Keyboard Enter/Space
+		this.tabDisposeables.push(DOM.addDisposableListener(tab, DOM.EventType.KEY_UP, (e: KeyboardEvent) => {
+			const event = new StandardKeyboardEvent(e);
+
+			// Run action on Enter/Space
+			if (event.equals(CommonKeybindings.ENTER) || event.equals(CommonKeybindings.SPACE)) {
+				this.editorService.openEditor(editor, null, position).done(null, errors.onUnexpectedError);
+
+				event.preventDefault();
+				event.stopPropagation();
+			}
+		}));
+
 		// Pin on double click
 		this.tabDisposeables.push(DOM.addDisposableListener(tab, DOM.EventType.DBLCLICK, (e: MouseEvent) => {
 			DOM.EventHelper.stop(e);