The Mozilla Thunderbird email client is generally a great program.  I use it to manage my ~10 different email accounts and have few complaints about it.  In fact, I was thinking of posting here just to say how great the color-coding feature is: it allows you to easily categorize the messages in your inbox by simply hitting a key from 1-5, and then you can tell at a glance which & how many messages in your inbox need your attention NOW!, or later..., or "in a week or two after I hear back from this person again", etc.

However the bugs that it does have are particularly irritating.  One is that since it’s built on the Mozilla codebase, it has all those annoying Mozilla bugs from 3 years ago that seem like they will literally never get fixed.  One particular bug that drives me crazy is that if Thunderbird is performing some action -- let’s say sending an email -- that fails and pops-up an error message box with an "OK" button, then Thunderbird will consume 100% of your CPU until you click OK.  (I think this is known as or related to the "throbber" bug: the throbber being the icon in the upper-righthand corner of the window that animates when the program is busy, and the bug being that when an error causes a pop-up message with an OK button, the throbber keeps throbbing (i.e. stays animated) until you click the OK button.)

But back to the topic of this post: the bug that’s currently bugging me is the one where your "default" SMTP server isn’t used by default.  In the account settings section, you can enter as many SMTP servers (outgoing mail servers) as you want, and you can label any one of them as "default."  This means that that particular server in your list is the one that will be used; the other servers will not be used.

Or at least, that’s what it’s supposed to mean.  In the Mozilla/Thunderbird world of mystery and suspense, things are sometimes not what they seem.  Or more to the point, things are not what they are labeled as.  The bug is that each of your email accounts (or "identities" or "personas", etc) has its own drop-down box which specifies the SMTP server that will be used for that account only.

So the resulting problem is that if you go into the SMTP server setup and set a different server as "default," Thunderbird doesn’t care: your accounts will continue to use whichever server they were using before.  The "solution" is to go into each of your 10 different email account’s individual settings sections and change the SMTP server there.  But the real solution would be for Thunderbird to replace the "Set as Default" button in the SMTP server setup with 2 new buttons: one called "Set as Default for Real" and one called "Set as Default Only for Newly-added Accounts, also known as ’The Old Sucky Way’".