If you stay in Thailand more than 180 days in a calendar year you become tax resident. If you then remit foreign sourced capital gains into the Kingdom the remittances are subject to tax. You are required to file a tax return if you remit assessable income above minimum thresholds in a year that you are tax resident.
there are no tax benefits from holding an Elite visa. Compare the DTV v Elite and you will see no one in their right mind would spend minimum 650k on a visa where a 10k visa gives similar advantages. Thus my statement that the DTV makes the Elite obsolete holds, there is no advantage.to an Elite over the DTV that is in anyway significant.