Sylpheed

For ages, IMAP IDLE has been missing in Sylpheed.

I combed the internet for this and apparently it was bugreported before, around 2008. No one of the developers ever answered that bugreport, or why IMAP IDLE is not even considered in the features. Around that time, someone even posted a patch, but it was discarded.

If you look online, missing support of IMAP IDLE is the number 1 reason for people to not use Sylpheed. It is /the/ biggest drawback, just consider this ordinary mail setup:

You have 2-5 Mail accounts, one private, one for work, another for work maybe, one for online registrations as a spamcatcher, maybe one at google because your phone requires a google account, maybe another one for another workplace, one for your open source projects maybe, and so on.
Your mail is 'cluttered', you have a lot of folders, just because you need to archive things and keep them in order easily accessible from everywhere. Because of this, each poll of your mail accounts takes a lot of time.
You need mail for work and need to receive new messages by the minute. Because of this, you have to set Sylpheed to poll as frequently as possible. Now here is the catch: If you set the polling frequency too low, people at work will get offended because your plus 10 minute delay disrupts communication. If it takes you 5 or 10 minutes to just reply to a one-liner with a one-liner, 5 times in a row, it is not nice. That's how people work nowadays though, they don't bother to use IM for it because it is unecessary and more complicated. I am a sysadmin and 10 minutes not knowing that the VPN or servers went down is crucial. Lots of other professions are no different.
On the contrary, if you set the polling frequency too high, the mailservers will get offended and at least one will block your poll every once in a while, causing Sylpheed to freeze even longer than usual (which means it is disabled for minutes).
Additionally, at every poll, you can't access your mail for a cuple of seconds (usually 3-15) and can neither send nor write messages. This can heavily disrupt workflow, especially if you write 20 messages or so within two hours.

Suffice it to say, if you want to use Sylpheed for work, you have a considerable problem. IMAP IDLE solves this by instantly notifying you about new messages and removing the unecessary block of using Sylpheed during polls. IMAP IDLE has drawbacks, but honestly, the advantages outweigh the disadvantages by far.

This feature is so important, I would do it myself if I had time and no one more qualified is available.

Or is there some questionable resentment against IMAP IDLE by the developers?