Correct me if I don't understand, but, when you talk about old layers, I suppose you're talking about a group of layers set as homepage, not the last session ?
If it's a group, it seems normal, not to use this group when you just open a shortcut on your desktop, or a link in your mail client. In this case, the feature works when just opening K-Meleon.
A+
Mozilla/5.0 (x11; U; Linux x86_64; fr-FR; rv:38.0) Gecko/20100101 Ubuntu/12.04 K-Meleon/76.0
Web:
http://jujuland.pagesperso-orange.fr/
Mail : alain [dot] aupeix [at] wanadoo [dot] fr
Ubuntu 12.04 - Gramps 3.4.9 - Harbour 3.2.0 - Hwgui 2.20-3 - K-Meleon 76.0 rc