If you are running Lion or later, it's because Apple thinks that they are smarter than you are. There is a new for Lion feature named 'Sudden Termination', and most Apple apps (including Preview) are rigged for it. Basically, if you have an app which can be Suddenly Terminated (and you can tell which ones by firing up Activity Monitor and having a look) then, if that app has been running for a while (and no, I don't know how long 'a while' is, I haven't experimented) without significant activity (and no, I don't know what Apple considers 'significant activity') then the system will terminate it without asking you. Unfortunately sometimes it terminates the app without notifying all concerned; this means that the icon vanishes from the Dock, or if it's permanently there, the 'app is in use' light will go away. However, some things, such as the Trash, don't get the message.
Work-around: don't put things into the Trash which are in use from an app which can be Suddenly Terminated. Other work-around: don't use apps which can be Suddenly Terminated. On 07 Jul 2012, at 16:35 , "Dinse, Gregg (NIH/NIEHS) [V]" <[email protected]> wrote: > Hi, > > A week or so ago, I wrote to ask why I could not empty the trash. Usually > the culprit is a PDF and usually I can quit the Preview app and then the > trash will empty. This did not appear to be the case recently, though at > least part of the problem turns out to be that the Preview app was still > running but its icon was not in the Dock, so I did not realize it was still > running (and thus I did not quit it). > > So the new question of the day is: Why does the Preview app disappear from my > Dock when it is still running? > > I have not investigated much, but if I double-click on a PDF while Preview is > not running, then Preview starts up and its icon shows up in the Dock, but at > some point (I don't know when or why), the icon disappears from the Dock. > > By the way, I discovered that Preview was still running by using the What's > Keeping Me app that someone suggested. Thanks for that suggestion! > > And thanks in advance for any information about my latest question. > > Gregg > > _______________________________________________ > MacOSX-talk mailing list > [email protected] > http://www.omnigroup.com/mailman/listinfo/macosx-talk _______________________________________________ MacOSX-talk mailing list [email protected] http://www.omnigroup.com/mailman/listinfo/macosx-talk
