Optgroup is a nest-able control for creating a heriarchy of grouped options within a SELECT element. When one optgroup is nested within another one, after the closing optgroup tag, the list appears to be out-dented.
I see this too (Linux build 2001-05-07-08).
OPTGROUP isn't nestable, according to the HTML 4.01 recommendation, so this would be invalid anyway. However, the browser should ignore invalid code, not go nuts. I'll try to get a testcase made to demonstrate the described situation.
The results are reasonable: In 2001060409 Win98, the browser is expecting users to leave their OPTGROUP tags open, so when it finds an OPTGROUP tag before the closing /OPTGROUP, it tries to start a new OPTGROUP as though the previous has ended, and disregards the extra closing tag later on. The recommendation does require an end tag, so it wouldn't be unreasonable to go ahead and support nested OPTGROUPS rather than behave this way, but that would be going above and beyond when at the same time Netscape's having enough trouble keeping the program from crashing and losing data. You can go ahead and change the OS to All, though.
17 years ago
*** Bug 92241 has been marked as a duplicate of this bug. ***
It makes you wonder what happened to proposals like this: http://lists.w3.org/Archives/Public/www-html/1997Sep/0347.html
They died the death of being involved with www-html.
Nested optgroups aren't allowed, and their contents are supposed to just be ignored, which will be fixed with bug 1214164.