Ghost notes not created from cross noteheads on unlinked tab staves
You cannot copy and paste crosshead notes from Staff into (unlinked) TAB if the crossheads were (newly) applied from the noteheads palette: they are converted into standard noteheads instead!
However you can copy and paste crossheads from TAB to TAB and from TAB to staff (where the notehead was originally created by shift + X). And when such a crosshead has been pasted from TAB to Staff it can then be pasted into TAB!
The program should allow crossheads created by double-clicking from the noteheads palette to be copied from Staff to TAB.