On Macs, Cmd+arrow is used to move to the beginning/end of the line.
With the new selection options, the shortcut defaults to moving within the segment and does not trigger a new selection even though the Edit menu emits a visual sign that an item has been triggered.
It would be preferable to assign a different shortcut to the selection. Besides, Ctrl+arrows triggers another OS action and should not be used...
Alt+Up/Down seems to work. Besides, Mac users are not generally used to Ctrl+Up/Down as used in other CAT tools, since most of them are Windows CATs, so a change would not make much difference to them.
I set the shortcut to Alt+Up/Down which works fine.
Fixed in the released version 3.1.6 of OmegaT.
Didier