splitview: use opacity to hide actions so that it does not break keyboard a11y

src/vs/base/browser/ui/splitview/splitview.ts

@@ -241,7 +241,7 @@ export class AbstractCollapsibleView extends HeaderView {
 		});
 
 		this.focusTracker.addBlurListener(() => {
-			setTimeout(() => dom.removeClass(this.header, 'focused')); // delay to give other components a chance to react
+			dom.removeClass(this.header, 'focused');
 		});
 	}
 

src/vs/workbench/browser/parts/sidebar/media/sidebarpart.css

@@ -29,12 +29,12 @@
 .monaco-workbench .viewlet .collapsible.header .actions {
 	float: right;
 	padding-right: 8px;
-	display: none;
+	opacity: 0; /* use opacity so that actions are still keyboard accessible */
 }
 
 .monaco-workbench .viewlet .collapsible.header:hover .actions,
 .monaco-workbench .viewlet .collapsible.header.focused .actions {
-	display: block;
+	opacity: 1; /* use opacity so that actions are still keyboard accessible */
 }
 
 .monaco-workbench .viewlet .collapsible.header .actions .action-label {

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

@@ -36,6 +36,7 @@
 .explorer-viewlet .monaco-count-badge {
 	padding: 1px 6px;
 	margin-left: 6px;
+	border-radius: 0; /* goes better when ellipsis shows up on narrow sidebar */
 }
 
 .explorer-viewlet .explorer-empty-view {

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

@@ -185,7 +185,8 @@ export class WorkingFilesView extends AdaptiveCollapsibleViewletView {
 		if (dirty === 0) {
 			$(this.dirtyCountElement).hide();
 		} else {
-			$(this.dirtyCountElement).show().text(nls.localize('dirtyCounter', "{0} unsaved", dirty));
+			const label = nls.localize('dirtyCounter', "{0} unsaved", dirty);
+			$(this.dirtyCountElement).show().text(label).title(label);
 		}
 	}