Others have already told you what I'm about to tell you, but I'll tell you anyway. Seems like it can't be repeated enough (and I will repeat a lot).
It wasn't a "bug", it was a bug! A real one. Much more real that the bug you're claiming. Believe it or not: the border-image didn't stretch correctly in 4.2.3, but it does in 4.3.0.
People who used border-image for what it was intended for, which is to provide a border image, got bad results in 4.2.3 because the image was stretched incorrectly. The corners were hideous, and people all around the world were very unhappy.
The border-image property was never intended to be used to set a background image. That's what background-image is for. Unfortunately for you background-image doesn't do what you want it to do, but that doesn't prove that the 4.3.0 behaviour of border-image is wrong. Once again: border-image was broken in 4.2.3 and it was fixed in 4.3.0. Fixing this was the correct thing to do.
Everyone who use border-image for what it is intended for, which is to provide borders without repulsive corners, are now happy because the corners are no longer looking nasty. Everyone who depend on the border-image bug in 4.2.3 as a hack to get stretched backgrounds are unhappy, but seriously, and please be honest now, do you really think that Trolltech should keep bugs in Qt so that people who are depending on these bugs will stay happy? Shouldn't they fix the bugs so that everyone who uses the feature for what it is intended for will be happy?
Your problem isn't that border-image don't stretch any more. Your problem is that background-image don't stretch. It never did and that is why you did your border-image hack in the first place. Let me repeat: the problem you are experiencing now is caused by a hack, this hack depends on a bug in 4.2.3, the hack was written by you and it's located in your code! It worked with 4.2.3, but it doesn't work with 4.3.0 and that's something you simply have to accept.
Now there are several alternatives for how you can handle this, but considering your rejection of the suggestions you already got from others I won't tell you unless you ask.
And just for curiosity: did you report this to Trolltech yet? If they tell you that this indeed is a bug and that border-image will be changed to stretch the image for 4.3.1, complete with appalling corners and everything, I'll not only eat my hat, but I'll also help you with building all future beta versions of Qt so that you can find the bugs and report them to Trolltech before the final releases.
Good day.
(Edit: the f-word replaced with something milder)
Bookmarks