missing add/edit virtual interface

With RouterOS v5.12, in Winbox, i am missing the option to add a Virtual Interface (vif).

Under the interface list, tab Interfaces, i cannot add it. And the existing ones, cannot be edited.
I can make a vif on the commandline on the shell interface..

Anybody else with the same issue?

WinBox v5.12 on RB1100AH (powerpc)