Hi Stephane,
You can avoid this additional tab before the braces by adding the following code to your form's constructor. Please refer the below sample that demonstrates this.
[C#]
CodeSnippet snippet = this.editControl1.GetSnippetByTitle("if");
snippet.Code = snippet.Code.Replace("\t", "");
I have attached the sample for your reference.
http://websamples.syncfusion.com/samples/Edit/I38257/main.htmPlease let me know if you have any other questions.
Regards,
Nagaraj