[Problem with Manage Printer menu]

You have to slide your mouse right along the right edge of the box until you can see the slider.  Once you know it's there, it isn't a big deal - and this works on other menu objects in Cura as well.  

[Problem with Manage Printer menu]

The display properties of Cura must be intended for people with really, really big monitors.  The scroll bars for that form are hidden/nearly invisible.  If you get right on the right edge of the window with the Ultimaker printers in it, you can eventually get the scroll bars to appear.  I'll try to get a screen grab off my other machine and post up.  

Once you get the scroll bars to move, all the printers show up like you would expect.

[Problem with Manage Printer menu]

Seeing the same issue.  The only printer options are Ultimaker printers