Setting the implicit animations to null doesn't reset the animations

[Sergio0694]

Describe the bug

When setting any of the implicit animations properties (eg. Implicit.Animations) to null after having previously set them, that doesn't actually reset the animations, but instead it does nothing. This also means that implicit animations can't be removed from eg. a visual state setter by setting the value of the attached property to {x:Null}.

Steps to Reproduce

Steps to reproduce the behavior:

1. Set some implicit animations to a UI element
2. Then set them to null (either in XAML or code behind)
3. Observe how the animations are still being played

Expected behavior

The animations should be removed when the relative property is set to null.

Environment

NuGet Package(s): 7.1.0

Package Version(s):

Windows 10 Build Number:

• Fall Creators Update (16299)
• April 2018 Update (17134)
• October 2018 Update (17763)
• May 2019 Update (18362)
• May 2020 Update (19041)
• Insider Build ({build_number})

App min and target version:

• Fall Creators Update (16299)
• April 2018 Update (17134)
• October 2018 Update (17763)
• May 2019 Update (18362)
• May 2020 Update (19041)
• Insider Build ({build_number})

Device form factor:

• Desktop
• Xbox
• Surface Hub
• IoT

Visual Studio version:

• 2017 (15.{minor_version})
• 2019 (16.{minor_version})
• 2022 (17.{minor_version})

Hello Sergio0694, thank you for opening an issue with us!

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