Trying to fix #772
More focus adjustments.
Selective psuedo-IsDefault.
fix focus navigation stuff
Merge pull request #1 from punker76/messagebox-focus-fix

fix for focus navigation stuff
FlatButton focus fix
MessageDialog focus button fix
Merge pull request #2 from punker76/messagebox-focus-fix

Messagebox focus fix
Merge pull request #773 from Amrykid/messagebox-focus-fix

Fix focus issues on the MessageDialog