In the Snippet tool, it is possible to edit in 2 ways :
- Subtractive mode (I select the part to be removed)
To do this, use the open scissors icon 
to cut what is placed between the begin cut mark (blue) and the end cut mark (yellow).
- Additive mode (I select the part to keep)
To do this, use the closed scissors icon 
to keep what is placed between the entry point (blue) and the exit point (yellow).
