Draw: Additional gluepoints don't exist after creating a group

Is that intentional ?

Not intentional, but it is a missing feature and a bug in some aspects.

https://issues.apache.org/ooo/show_bug.cgi?id=7575

https://issues.apache.org/ooo/show_bug.cgi?id=61439

https://bugs.freedesktop.org/show_bug.cgi?id=76277

https://bugs.freedesktop.org/show_bug.cgi?id=45863