Hi Harmen,
[quote user="Harmen gro�e Deters"]as an XAttribute as I understand[/quote]
Yes, it's correct .... in fact the most of settings and internal data are now stored as XAttributes.
[quote user="Harmen gro�e Deters"]Is there a better way to do this?[/quote]
You can try to use Addin.XAttributeChangedEvent.
I am also not sure ComApp.AddChangeTrackEventsHandler is equal to Addin.ElementChangedEvent or their functionality is different, so you can test it also.
In general C# API how it's implemented in V8i (COM API) is not a proper tool to achieve what you want (but I guess XAttributeChangedEvent should work in your case).
It's recommended to use native API to do any monitoring of design file changes at least for two reasons: It's substantially more efficient (no marshalling through COM API between native and managed code) and also it provides bigger flexibility what events can be monitored.
With regards,
Jan