Green connection balls in VAB keep disappearing

[THX1138]

I'm having a hard time in the VAB. Any idea why the green connection balls keep disappearing? Is it a known bug?

See the small fuel tank in this screenshot? It used to have a connection ball and now it doesn't. Not cool.

Edited December 25, 2014 by THX1138

[Anquietas314]

I'm pretty sure that's a bug. You should add the information requested in the bug reporting guidelines (I should really just stick that in my signature at this point...)

[numerobis]

I've seen that a lot myself, haven't tried to come up with a repro case.

Workaround: Save your spacecraft and reload it, or exit to the space center and reenter the VAB.

[RexKramer]

The HubMax adapter, and other adapters with 6 in-line attachment points, have a known issue, especially when using symmetry. It's bug #2882.

Unfortunately, I'm not aware of a good workaround, except try using different parts to achieve your goal.

For example, mount four BZ52 radial attachment points (with 4X symmetry) on a structural fuselage or fuel tank section, you'll accomplish a very similar structure to what you have in mind.