It still happens. You open a window in GP version 10 or 2010 and then click off that window and it minimizes to the task bar.
Well that's what it looks like but that is not what is really happening.
With Version 10, GP adopted the normal independent windows model. Each window is an independent task and when launched, it appears listed in the task bar. When you click off of that window, some other window comes to the front and frequently covers or hides the first open window. The window is not minimized, it is covered!
If you are running GP with the home page full screen, all additional windows will "disappear" everytime you click on the home page. Click on the multi-window icon in the upper right corner of the window to show multiple open windows on your desktop.