When entering words like
ความดันสถานะเสื่อมของอิเล็กตรอน (random word)
it is displayed correctly, buf if one moves the cursor through the line it doesn't move char by char but limps. At the end some blanks (or invisible chars, idk) appear, which cannot be removed directly. Perhaps it might be caused by an implementation problem of the vowel handling.

The recently created https://commons.wikimedia.org/wiki/Special:AbuseFilter/315 shows that problem.