Having problem with Thai vowel characters

I am having with some vowel character of Thai language* as some are displaying fine but some are being cut off.

  • Thai vowels are usually above and below the main character for example กำลัง the characters are ก and ล but those two have corresponding vowels -ำ with ก and -ั with ล

As shown in the image the above is from Nextion editor and below is from MS Word (Same font, same word)