Running multiple instances of a program isn't a limitation of the operating system, but the application itself. If the program only allows one instance, then when you attempt to run the program a second time, it will check to see if an instance is already running, and stop the attempt to start it again.
Apparently, however, there is a way to run multiple instances of Tickr. You will need some knowledge of batch files -look here
(at the very bottom) for some guidance.
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