only one instance of an application at a time?

You can open multiples of the same application by using Terminal.

open -n -a TextEdit
open -n -a iPhoto

etc.

You should keep in mind that, unlike Windows applications, Mac apps are not designed to be run that way. Most Mac applications have other ways to accomplish what you want, such as by opening multiple windows.

Using a workaround to run multiple copies of an application should be done at your own risk. Many write to Library or other files, which could be problematic with multiple access.

This behavior on the Mac is done on purpose and is a result of a lot of careful consideration. It is not a limitation that needs to be fixed.

If you really want to run an application twice and can't or don't want to use the Terminal method that Király mentioned, you can make a copy of the application and run that.

But my warning still stands, that Mac applications are not designed to run that way and may not work. iPhoto is an example. You could really mess up your iPhoto library if you had multiple instances running.

Message was edited by: deh2k

If you're talking about the Microsoft RDC, then YES, you can run many sessions at one time. You'll need the "Microsoft Remote Desktop Connection Client for Mac 2 (Beta 3)" for this functionality.

http://www.microsoft.com/mac/downloads.mspx?pid=Mactopia_RDC&fid=6671113A-8601-4 2B9-BCB5-CEEC68F81090#viewer

hth

The point is that you don't have to run multiple instances of Microsoft RDC in order to connect to more than one remote host. Read the documentation for the application to find out how to do it.

The previous session is likely just hidden by the new one.

Try to Cmd-TAB and switch windows.