Welcome to the SeeMeCNC Community

I have a question about editing the custom G-Code in the MatterControl.
I am trying to add in the Starting G-Code a line of code to start the fan at 50%
M106 S50
I can add and hit the save button with no issue.
It seems to have saved it in the Start G-Code section.
However, when I try to save the part I am working on this code does not seem to be inserting
into the part G-Code.
Why are these custom code changes not saving in my parts?

The same was happening to me.

I think that editin a preset solved the problem.

Going in and saving the preset did the trick.
Thanks Teoman.