src/vs/workbench/browser/parts/editor/editorGroupView.ts/EditorGroupView/doStickEditor
class EditorGroupView:	private doStickEditor(candidate: EditorInput | undefined, sticky: boolean): void {
		if (candidate && this.model.isSticky(candidate) !== sticky) {
			const oldIndexOfEditor = this.getIndexOfEditor(candidate);

			// Update model
			const editor = sticky ? this.model.stick(candidate) : this.model.unstick(candidate);
			if (!editor) {
				return;
			}

			// If the index of the editor changed, we need to forward this to
			// title control and also make sure to emit this as an event
			const newIndexOfEditor = this.getIndexOfEditor(editor);
			if (newIndexOfEditor !== oldIndexOfEditor) {
				this.titleAreaControl.moveEditor(editor, oldIndexOfEditor, newIndexOfEditor);

				// Event
				this._onDidGroupChange.fire({ kind: GroupChangeKind.EDITOR_MOVE, editor });
			}

			// Forward sticky state to title control
			if (sticky) {
				this.titleAreaControl.stickEditor(editor);
			} else {
				this.titleAreaControl.unstickEditor(editor);
			}
		}
	}