Subject pretty much says it all.
tabs.ini gets blanked on startup, and therefore the session.
I am getting the usual
/* Saving backup file to "C:\Users\Arffeh\AppData\Roaming\HeidiSQL\Backups\query-tab-2019-09-12_10-47-06-388.sql"... */ when editing queries, which are correctly saved in Backups and tabs.ini .
However on each application startup, it completely disregards tabs.ini and starts over.
The HeidiSQL\Backups folder is proceeding to fill quite rapidly.
Using 5683 and restoring my tabs from a nightly backup worked.