Creating sectors inside a sector does not properly define sidedefs

[mistersector]

Undefined lines in a sector:

Dragging the vertex over each other merges the vertex, but does not create a sector or a VOID from the lines.

Switching to sector mode and pressing space while the mouse is hovered over the undefined space creates a new sector, however it uses the default sector properties instead of copying attributes from the surrounding sector.

Hovering above the outside sector reveals Eureka only created a sidedef for the first sidedef, even though it should have 2 sidedefs because it is inside a sector:

Over on the sidebar, the second sidedef is undefined. If I hadn't turned on the option to see the ADD/DEL buttons, I'd never know what was wrong.

Pressing ADD defines the second sidedef.

I'd like Eureka to not only create a second sidedef during this condition, but allow a hotkey modifier when I press space in sector mode to create a VOID instead.

Alternately, create the correct sector or VOID when I merge the vertices instead of requiring me to enter sector mode and manually create the sector.