@Bob *********
your information is out of date.
Thailand uses the 180-day rule to determine tax residency. If you are physically present in Thailand for 180 days or more in a calendar year, you are considered a Thai tax resident under Thai law, whether all income is foreign or not. This rule is applied by the Thailand Revenue Department, regardless of visa type. You don't necessarily need to pay anything, but you do need to file.
Sources:
• Thailand Revenue Department guidance on personal income tax residency
• Thai Revenue Code, Section 41
• PwC Thailand tax summary (mirrors Revenue Dept interpretation)
Visa status and tax residency are separate issues. Being on a DTV, ED, Elite, etc. does not override the 180-day tax residency rule.