You can disable the stickyness via your settings under 'Preferences':


Yes, people have been noticing this on all sites throughout the Stack Exchange network. There's a 'central' bug post on the Main Meta which has now been marked status-completed, meaning it should be resolved.


Yes, this is the so-called Custom Filters feature, which has been released today after being alpha-/beta-tested for almost a year as Custom Question Lists. You can find most information you're looking for in the first link, which leads to the announcement of the feature on Meta Stack Exchange.

Only top voted, non community-wiki answers of a minimum length are eligible