Closing all files in a group except for a markdown file does not update...

Closing all files in a group except for a markdown file does not update overflow control icon (fixes #6795)

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

@@ -483,7 +483,7 @@ export class EditorPart extends Part implements IEditorPart {
 			this.doCloseActiveEditor(group, focusNext);
 		}
 
-		// Closing inactive editor is just a model update
+		// Closing inactive editor is just a model and title update
 		else {
 			this.doCloseInactiveEditor(group, input);
 		}
@@ -510,6 +510,9 @@ export class EditorPart extends Part implements IEditorPart {
 
 		// Closing inactive editor is just a model update
 		group.closeEditor(input);
+
+		// Update UI
+		this.sideBySideControl.updateTitleArea({ position: this.stacks.positionOfGroup(group), preview: group.previewEditor, editorCount: group.count });
 	}
 
 	private doCloseGroup(group: EditorGroup): void {
@@ -628,6 +631,9 @@ export class EditorPart extends Part implements IEditorPart {
 
 			// Update stacks model: close non active editors supporting the direction
 			group.closeEditors(group.activeEditor, direction);
+
+			// Update UI
+			this.sideBySideControl.updateTitleArea({ position: this.stacks.positionOfGroup(group), preview: group.previewEditor, editorCount: group.count });
 		}
 
 		// Finally: we are asked to close editors around a non-active editor

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

@@ -1200,12 +1200,23 @@ export class SideBySideEditorControl implements ISideBySideEditorControl, IVerti
 			let input = editor ? editor.input : null;
 
 			if (input && editor) {
+
+				// Pinned
 				const isPinned = !input.matches(state.preview);
 				if (isPinned) {
 					this.titleContainer[state.position].addClass('pinned');
 				} else {
 					this.titleContainer[state.position].removeClass('pinned');
 				}
+
+				// Overflow
+				const isOverflowing = state.editorCount > 1;
+				const showEditorAction = this.showEditorsOfGroup[state.position];
+				if (isOverflowing) {
+					showEditorAction.class = 'show-group-editors-overflowing-action';
+				} else {
+					showEditorAction.class = 'show-group-editors-action';
+				}
 			}
 		}
 	}