It's sometimes needed to enter !important in inline CSS styles. But if you try to do it, for example, with this code:
<div style="width:50% !important">
the generated wikitext will contain
<div style="width:50% !important">
This   breaks style and some functionality.
Version: 1.12.x
Severity: normal
URL: http://ru.wikipedia.org/wiki/Template_talk:Ambox
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=3158