To provide optimal user experience and quick startup DeltaWalker employs a mechanism that allows you to open new comparison windows in an already running instance if there is such.
DeltaWalker is capable of launching new application instances—Window > Open in New Window—that, in all aspects, behave just like the individual instances you would launch from the command line, except that they launch faster. DeltaWalker leverages this functionality to ensure fast startup times for all subsequent invocations of DeltaWalker after the first one.
Launching a file or a folder comparison from the command line by default opens a new comparison window inside an already running DeltaWalker instance and brings that instance's window to the front of the applications on your desktop. By a large margin of user votes, this is regarded as the most intuitive and performance/resource considerate way of launching new file or folder comparisons from the command line.