You can have multiple tabs.. But you can only have two panels. and there is a reason for that.
MC is designed around the dual panel layout, where the panel that is in focus all the default source location, and the other panel is the default target location.
A lot of commands and features in MC is using this.. and if there was more panels it would not work well. because if there are 3 panels then you have two that are "not in focus" so which of them are the default target location ?
