Missing TypeId override in attributes with AllowMultiple set to 'true'

[MarqueIV]

For attributes such as CategoryOrderAttribute, you must override the TypeId property or else the TypeDescriptor will not properly find them.

Add this line to the class...

public override object TypeId => Category;

[MarqueIV]

Actually, I read up on how to create a PR here, and did! :)

#1523

[XceedBoucherS]

Thank you for bringing this to our attention.
The fix will be included in v3.9.