#712 Remember groups status (expanded/closed)

[Olivier Keshavjee]

Now, the options regarding groups allow either to have them all expanded on JabRef opening, or all closed.

When I work on a specific topic for a while, I usually have the same groups expanded/closed, and each time I open JabRef I need to expand/close them.

A very useful feature would be to remember the states of the group when JabRef exists.

[fdar]

Same as https://sourceforge.net/p/jabref/feature-requests/856/

[Tobias]

Tracked at https://github.com/JabRef/jabref/issues/1428