Originally Posted by el_sheepo
I tried changing the default account and all new messages were sent by the address of the default account after that. I changed it back and the effect was reverted, so everything works as expected.
Not sure why this doesn't work for you.
For some reason, the account I would like to set as default cannot be installed on my device. I have it working fine on the web but when i try on my handheld, it says it cannot be verified. I emailed tech support.