https://learn.microsoft.com/en-us/uwp/api/windows.ui.xaml.controls.inktoolbar.activetool?view=winrt-28000
InkToolbar.ActiveTool Property (Windows.UI.Xaml.Controls) - Windows apps | Microsoft Learn
Gets or sets the currently selected feature in the "tools" group of the InkToolbar (see remarks). This property provides access to the following objects:...
propertywindowsuixamlcontrols