Running Omniscope on Windows allows you to have a number of files open in different Omniscope instances at a time. On a Mac if you try and open an Omniscope file when a file is already open it prompts you to shut down the first file to open this new file. If you want to open a second (or third) instance of Omniscope, open a terminal window (from Applications/Utilities or by typing terminal in the spotlight search). When the terminal window is open type the following command:

open -n /Applications/"Visokio Omniscope.app"

this will open another Omniscope instance and you can open a second file and work with it as normal.