~jaro/balkon

ref: ce4f4845a30de2bbcbce4c8c9eb2a0607b57588d balkon/src/Data/Text/ParagraphLayout/Internal/ProtoLine.hs -rw-r--r-- 3.7 KiB 
Allow explicit control of box collapsing.

Add extensible filter for invisible lines.

Handle ancestor boxes in rich layout.