Why does software update re check after updates are installed when you show updates When updates are available you have the choice of install or show details.  When you click install the updates are installed then you have to close the updater.  When you click show details then install after the update it checks again for updates then shows you the updates you just installed but they are unchecked.

Is this just a flaw in the UI or is there some reason for this?  How come the updater doesn't alert you after the install then close itself.  This has always really annoyed me for some reason.
It appears that some updates have others as prerequisites, and will not show up as available until the others are installed. Thus, Software Update makes a list of all eligible updates, then runs. If a subsequent update was also pending that was not eligible to be downloaded because its prerequisite has not not yet been installed, that update would not make the list. The subsequent check, however, would see if any new updates had been unlocked by the updates installed.