The current layout of the link tab in Task Properties allows only the side by side windows of the predecessors and successors, making the function of "Customise columns" inefficient.
The user has the option to bring in and make visible a vast set of columns, but there is simply not enough room for the user defined columns to fit in the existing setup.
In P6 the user has the option to change the layout from side by side to over and under or even to separate windows.
This would help a lot with productivity and would make Synchro more P6 user attractive.