Changed the access to many native classes and structs from public to internal
Extract the dialogs header and message font sizes into the Fonts.xaml resources
It's the dialog title, not the header
Merge pull request #1579 from MahApps/internalize-things

Changed the access to many native classes and structs from public to internal
Split the ControlsHelper class into multiple more granular classes
Move more attached properties around
removed superfluous deregistration of local hander of local event. After the finalizer is executed neither will the event occur ever again nor can the handler hinder garbage collection.
Furthermore the usage of the Dispatcher can proof dangerous if used when doing AppDomain.Unload (possible deadlock?!)
removed superfluous "emptyDelegate" definition.
Missed a type change

Thanks for the thrown "KeyNotFoundException", WPF
Merge pull request #1584 from BrunoJuchli/master

Preventing deadlock on AppDomain.Unload by removing superfluous finalization logic which uses Dispatcher.
Document that the Flyout's CloseCommand won't execute when IsOpen is set to false
removing superfluous finalization code, as per https://github.com/MahApps/MahApps.Metro/issues/1591
Merge pull request #1592 from BrunoJuchli/master

removing superfluous finalization code, as per Issue #1591
GroupBoxHeaderForeground -> HeaderForeground
Merge pull request #1582 from MahApps/split-controlshelper

Split the ControlsHelper class into multiple more granular classes