[Bug] Changing BorderThickness will cause an exception to be displayed when nodes are selected #70

Describe the bug
If BorderThickness is changed to a value not equal to 1, it will cause an abnormal display when the node is selected. If it is selected, the node will move slightly
Modifying BorderBrush will cause SelectedBrush to be modified together and the SelectedBrush modifications to be invalid
It is also not possible to change the Selected BorderThickness
To Reproduce
change ItemContainer style

Expected behavior
No displacement

Screenshots

Additional context
Add any other context about the problem here.