Custom Tags throw errors

[JayantVarmaTLS]

If there is a custom tag that is declared in the associated class, the tags are not parsed, the name spaces cause errors.

Some examples of errors:

Property Button.Clicked was removed since it's currently not supported.
<Button Text="Press Me" Clicked="OnPressHandler" />

Missing Design Time Data

<x:Array Type="{x:Type x:String}">
 <x:String>Mono</x:String>
 <x:String>Stereo</x:String>
</x:Array>

Root XAML element unrecognized, nothing to display and any other custom tags created with a class or as a reference

xmlns:local="current.solution.name"
Root element local:CustomClassName was not recognized, nothing to be displayed.