The most frustrating thing to me about Logos 4 is the lack of resizable windows and more than 3 or 4 windows. The tab feature is handy for some purposes. But I often want to have several passages open in the same Bible version at the same time. For example, I want to look at several Synoptic Gospel accounts of the same story. Frequently I want to have the Old Testament open in English in one window, with the Hebrew and sometimes Septuagint open in another window. These are linked as set A. Then I have the New Testament open in English and Greek linked as set B. This lets me compare the Old Testament citation in the New Testament. At the same time I have commentaries open and lexicons, all in separate windows.
Unless I am missing something very basic, I don't see any way to open more than 3 or 4 windows. I also don't see any way to open up more than one copy of a given Bible.