Xnsketch - Effect is immedately applied on file open

[capecutterman]

First of all, thank you Pierre for all your wonderful free-for-home-use software!

XnSketch v1.18 on Windows 10 1703

When I open an image an Effect is immediately applied (Black and White in my case), there seems to be no provision for No Effect/Original, as there is in the Mask tab. Why is there no Original choice under the Effect Tab?

If I want to apply a Mask, rather than an Effect, this is rather frustrating - in fact it makes XnSketch of limited value to me.
I have tried various combinations to no effect.

Am I overlooking something?

Merci bien - André