Hi, Welcome to the Forum temoins-de-yehovah!
Here are all important links:
http://lmms.io/forum/viewtopic.php?f=1&t=4740
-A few rules and useful forum instructions
Not in current 1.2.1exist ghost note in last version of lmms ?
You can use a 'hack' https://www.youtube.com/watch?v=xTF8s2AxknA