Hi folks,
The current common line implementation works only when both lines start and end at the same points.
When nesting, we often end up with 2 parts touching that only have part of the line in common.
Eg:
+-------------------+
| |
| |
| 1 2 | 3
+-------+-----------+----------+
| |
| |
+----------------------+
Where line section 2 is a candidate for merging, but does not appear to be handled currently.