For whatever reason, Settings.Designer.vb was auto-modified in a way that created this issue. I check with several other applications that were working correctly and compared the format of the Settings.Designer.vb file.
What I found:
In the application where the My.Settings objects were broken, the class "Settings" was contained within the namespace My.
The bottom of this file also contained:
Namespace My
<Global.Microsoft.VisualBasic.HideModuleNameAttribute(), _
Global.System.Diagnostics.DebuggerNonUserCodeAttribute(), _
Global.System.Runtime.CompilerServices.CompilerGeneratedAttribute()> _
Friend Module MySettingsProperty
<Global.System.ComponentModel.Design.HelpKeywordAttribute("My.Settings")>
Friend ReadOnly Property Settings() As Global.MaverickDesktop.My.Settings
Get
Return Global.MaverickDesktop.Settings.Default
End Get
End Property
End Module
End Namespace
Removing the first namespace entries around the Settings class and modifying the above to:
Namespace My
<Global.Microsoft.VisualBasic.HideModuleNameAttribute(), _
Global.System.Diagnostics.DebuggerNonUserCodeAttribute(), _
Global.System.Runtime.CompilerServices.CompilerGeneratedAttribute()> _
Friend Module MySettingsProperty
<Global.System.ComponentModel.Design.HelpKeywordAttribute("My.Settings")>
Friend ReadOnly Property Settings() As Global.MaverickDesktop.Settings
Get
Return Global.MaverickDesktop.Settings.Default
End Get
End Property
End Module
End Namespace
This resolved the issue ... but doesn't give me a warm and fuzzy feeling.