@John *********
Being a permanent resident in Japan, if I sold a property in Estonia (mine for 35 years), I will have to report it in Japan and pay tax on the sale (whatever it is) in Japan.
Thais are not unique about that.
My American friend, an English teacher in Japan, told me, if he earns more than 80K US$ a year (he does not earn that much) he will have to pay tax in the US as well.
Only USA and North Korea (!!!) have that same tax law.