can't seem to find an option to save password or setting to enable it either? has this feature been removed in 3.0?

No it's still there. Do you have a group policy that disables password saving for Remote Desktop? In RD Tabs 2.x there was a setting to explicitly enable/disable password saving, but that was removed for 3.0 and password saving is allowed all the time except for unless a GPO disables it.