ผู้ที่มีประวัติการดรอปเรียน ไม่สามารถสมัครขอทุนศึกษาต่อปริญญาโท (ส่วนใหญ่) ได้

I think it's case-by-case, depends on the reasons.
At my "table" (means ==> group), we had every year
student who "dropped" but we went for exchange program/internship abroad.
Many of us later got scholarships directly from our school, Kor Por, Bank
or other universities abroad. It's never been a problem for us.
(Actually, it migh be advantages to get a scholarship or to get a job.)

I, myself wasn't effected from this "drop".

==If you drop because of your personal reasons, things might be different.==
Any way, best thing is check with your Register Office.