I found this bug in 23-12-2016 example: use this small snippet reg #cs     ; a #CE #include <Array.au3> #include <MsgBoxConstants.au3> #include <Process.au3> Fold them all. Focus cursor in first line just after reg and hit spacebar. It seams this is the same bug. It is already reported to scintilla dev team:  https://sourceforge.net/p/scintilla/bugs/1896/