Aptitude -- Packages being held back
Today I went to install a package using aptitude.
When I hit the "g" key to get the review of what aptitude will install, there was a considerable list of packages shown under the heading of Packages being held back.
The explanation in the lower part of the screen states that these packages could be upgraded but won't be because I've requested them to remain at there current version.
The problem is, It's my box and I have made no such request.
Is this the normal behavior of aptitude?
Naturally all of the packages are listed as installed. Most, but not all, also have an A tag, which, if I'm not mistaken, indicates it was installed as a dependency. All are also tagged with a U, which I thought meant to upgrade that package but obviously I'm wrong.
Could somebody please explain this behavior?
I realize all I have to do is select the heading and press the + to have the packages upgraded but I'd like to understand why the system believes I've issued the hold command.