Missing dash separating filename from Code application title (fixes #20236)

src/vs/base/common/labels.ts

@@ -189,7 +189,10 @@ export function template(template: string, values: { [key: string]: string | ISe
 
 			// Separator
 			else if (resolved) {
-				segments.push({ value: resolved.label, type: Type.SEPARATOR });
+				const prevSegment = segments[segments.length - 1];
+				if (!prevSegment || prevSegment.type !== Type.SEPARATOR) {
+					segments.push({ value: resolved.label, type: Type.SEPARATOR }); // prevent duplicate separators
+				}
 			}
 
 			curVal = '';

src/vs/base/test/common/labels.test.ts

@@ -125,6 +125,7 @@ suite('Labels', () => {
 		t = '${dirty}${activeEditorName}${separator}${rootName}${separator}${appName}';
 		assert.strictEqual(labels.template(t, { dirty: '', activeEditorName: '', rootName: '', appName: '', separator: { label: ' - ' } }), '');
 		assert.strictEqual(labels.template(t, { dirty: '', activeEditorName: '', rootName: '', appName: 'Visual Studio Code', separator: { label: ' - ' } }), 'Visual Studio Code');
+		assert.strictEqual(labels.template(t, { dirty: '', activeEditorName: 'Untitled-1', rootName: '', appName: 'Visual Studio Code', separator: { label: ' - ' } }), 'Untitled-1 - Visual Studio Code');
 		assert.strictEqual(labels.template(t, { dirty: '', activeEditorName: '', rootName: 'monaco', appName: 'Visual Studio Code', separator: { label: ' - ' } }), 'monaco - Visual Studio Code');
 		assert.strictEqual(labels.template(t, { dirty: '', activeEditorName: 'somefile.txt', rootName: 'monaco', appName: 'Visual Studio Code', separator: { label: ' - ' } }), 'somefile.txt - monaco - Visual Studio Code');
 		assert.strictEqual(labels.template(t, { dirty: '* ', activeEditorName: 'somefile.txt', rootName: 'monaco', appName: 'Visual Studio Code', separator: { label: ' - ' } }), '* somefile.txt - monaco - Visual Studio Code');