I have lived in Singapore and KL for 7 years now. Long sleeve shirt would be expected in Singapore - and sometimes tie. Usually noone wears a tie; the Prime minister does not. KL is more fomal than Singapore. In KL always tie and sometimes also a jacket. Business places have good air conditioning.

Tourists in shorts are frowned upon - in both cities. You rarely see locals who wear shorts. It is a matter of decency - cover yourself up! They would of course never tell you. This is not only the muslim influence - the Chinese and Indians have also adopted the same style. So bring some long pants of cotton - I always use them. You wil l get more rrespect and credibility!

Similarly - you rarely see young couples hugging and kissing in the street.
They may not even hold hands!

Mahel