I find it hard to believe that WordPress programmers would leave a bug so obvious as the Text Widget Text Selection Bug in WordPress 2.3.1.
No such bug exists. I'm able to select text in the text widgets just fine with 2.3.1.
login logout error message bug
Again, no such bug exists. I do not see what you're describing on any 2.3.1 site.
bugs like these need to be caught and fixed because they are so dad burned obvious.
Whatever the problem is, we're willing to help you solve it, but we cannot help you if you're just going to shout "fix it! fix it!" and not actually attempt to fix your site in particular. Because that's where the bug is: Your site. It's not on ours.
Note: if there is a bug, it's a bug that doesn't show up on the majority of WordPress installations. So when you think it's "dad burned obvious", you're wrong. It's not obvious, because we don't see it on our sites. If we did, we'd fix it. Obviously.