Application compatibility is one of the most difficult obstacles users face when migrating from Windows XP to Windows 7. XP Mode is a pre-packaged VHD (virtual hard disk) that auto-logons when launched. When applications are installed in XP Mode, they appear as stand-alone apps in Windows 7, showing up under the menu bar. Most users probably won’t notice that they’re running a particular app in virtualization mode, other than the conspicuous slowness they’ll experience after booting up.”]
Source: https://www.csoonline.com/article/2629391/windows-7-security-primer–part-two.html