KDE Tip: Split-view in Dolphin, KDE's file manager

Whenever you are working with files in KDE's Dolphin it can be useful to split the current view into two panes, allowing you to drag and drop files between two locations, or allows you to monitor places for new downloads.

Wherever you are in Dolphin, you can press F3 to split the view or click the split button atop.

Source

http://techgage.com/article/ten_kde_4_tricks_worth_knowing_about/