Inconsistencies of "Table of contents"

[WHISK4S]

To re-enact the issue.
Start Abricotine with a blank page

• enable 'table of contents'; View -> Show Table of Contents
• do NOT close the window
• use a file manager to open a Markdown file

This which would call another Abricotine instance
the new instance would NOT show a ToC on the sidebar
Notice the menu item; View -> Show Table of Contents :: is ENABLED (but not showing)
When toggling the ToC; it now function as Enable is to hide, Disable is to show

abricotine_1.1.4_amd64.deb (dark theme, thank you!!)
elementary OS 5.1.7 Hera, Gnome (Gtk 3.22.30-1ubuntu4), 5.0.0-37-generic x86_64

[fdutheil]

Hello.
Quite a long standing issue, had it with version 1.0 already. Thanks for reporting it :)