Sorry I’m not sure I follow your explanation. Surely one has a plane for a reason: a low impedance path, screening, providing a Heat-sink for example. The point is, they and connected, I personally and from experience can not think of a reason why a plane would never be connected some where .
The option name “Connection Style” and a bit of code digging suggests it’s associated with the connection between the plane and any device pin on the same net. That is; not connected (None) or fully connected (Solid), the connection could of coarse be a thermally relived connection (an option not currently available) but that takes this off topic.
As mentioned I did do a bit of code digging and I think I found a bug with the None option. First I’m assuming when Plane Rebuild is selected it should fully fill the plane regardless of the Connection Style ( a bug? ). This would make sense since there is a separate UI control to hide (right click visible) the plane for easier trace editing.
I have also discovered by adding a trace from any device pin on the same net as the plane and for a short distance, say 1mm, then the None option and Rebuild Plane selected result in a clearance around pads. This provides some interesting possibilities. See the simple picture below.
Having to add an overlapping trace suggests a second bug.