Welcome to TVPaint Community forums !

Just to get this clear
the FX Stack is Destructive like Photoshop??
If you apply the FX you cant undo??

and it is not possible to work like in After Effects, where the FX dont change the source?

-mads

When you apply your FX Stack on the source layer the result with modify the source layer but you can undo it if the result is unwanted.
If you want to keep your source layer unchanged, just use the "Source Image" FX. Thanks to him you can have the result on a different layer. How to proceed :
- Create a new layer for the result and set it as current,
- Select the Image Source FX in the FX Stack and choose what (layer, project, etc...) will be use as source for your FX Stack,
- Select and set all the FX you want to apply,
- Sellect all image (on the result layer) where you want apply the FX Stack and apply it.
=> The resulting images will be added on the result layer (don't forget it must be the current one) and the source will not be modify. You should hide the source since it is a part of the result.