We've been receiving reports that our client is broken because after playing with Tremfusion people's configs are saved in different locations and in different ways (and hence the settings they use with it aren't found by other clients). When switching back to tremfusion they of course find that the standard client has tried to rewrite the settings as it expected to find them and their settings are now lost for both clients.
Yep, it's official: TremFusion breaks compatibility with other clients. Attempting to go back to another client after using tremfusion will be difficult for obscure reasons, and the likely outcome is you will lose your settings for both clients.