Manage optional TOC instance in ScrollPane.
Manage optional TOC instance in ScrollPane.

abhaga/substance,abhaga/substance,TypesetIO/substance,substance/substance,stencila/substance,michael/substance-1,podviaznikov/substance,michael/substance-1,jacwright/substance,andene/substance,TypesetIO/substance,substance/substance,jacwright/substance,podviaznikov/substance,andene/substance