Here is my log file with the two relevant entries:
(At my first trial I didn't found the relevant entries!)
2016-03-30 12:01:37,176 1151 INFO ? werkzeug: 127.0.0.1 - - [30/Mar/2016 12:01:37] "GET /web_editor/static/src/js/snippets.options.js HTTP/1.0" 200 -
2016-03-30 12:01:37,207 1151 WARNING ? openerp.http: Logged into database 'test', but dbfilter rejects it; logging session out.
2016-03-30 12:01:59,159 1151 INFO ? werkzeug: 127.0.0.1 - - [30/Mar/2016 12:01:59] "GET /web_editor/static/src/xml/snippets.xml?debug=1459339218287 HTTP/1.0" 200 -
2016-03-30 12:01:59,383 1151 INFO ? werkzeug: 127.0.0.1 - - [30/Mar/2016 12:01:59] "GET /web_editor/static/src/xml/translator.xml?debug=1459339218461 HTTP/1.0" 200 -
2016-03-30 12:01:59,423 1151 INFO test werkzeug: 127.0.0.1 - - [30/Mar/2016 12:01:59] "POST /web/webclient/bootstrap_translations HTTP/1.0" 200 -
2016-03-30 12:01:59,445 1151 INFO test werkzeug: 127.0.0.1 - - [30/Mar/2016 12:01:59] "POST /web/proxy/load HTTP/1.0" 200-
2016-03-30 12:01:59,508 1151 INFO test werkzeug: 127.0.0.1 - - [30/Mar/2016 12:01:59] "POST /web/webclient/translations HTTP/1.0" 200 -
2016-03-30 12:02:05,617 1151 INFO test werkzeug: 127.0.0.1 - - [30/Mar/2016 12:02:05] "GET /web?debug HTTP/1.0" 303 -
2016-03-30 12:02:05,796 1151 INFO test werkzeug: 127.0.0.1 - - [30/Mar/2016 12:02:05] "GET /web/login HTTP/1.0" 200 -
2016-03-30 12:02:21,176 1151 WARNING test openerp.addons.base.ir.ir_cron: Method `bus.presence.check_users_disconnection`does not exist.
What do you see when try the database selector: subdomain.domain.tld/web/database/manager ?
Also my regexp looks like ^%d$ , I don't know if the $ sign makes a difference.
@Erwin I see all the database in the databse selector that have an identical beginning of the db-name. Eg. If my domain is demo.domain.tld and I have also a db called demo_xx I cann see this one too. I can't imagine that the $ sign at the end of your dbfilter regexp makes a different? But I should try: on the difference dee: https://www.odoo.com/de_DE/forum/hilfe-1/question/domain-based-db-filter-6583
The $ seems not the issue in this case. The reason why I'm asking is that I experience also strange behaviour with logouts when I'm using Odoo without dbfilter, means while having access to a list of several databases. A new login by selecting the appropriate database from the list solves the problem. I definitely do not have any problems as long as dbfilter identifies exactly 1 database which should be the case in production mode anyway if you want to avoid different kind of problems.
I don't remember if it makes a difference if you properly log out before selecting another database and then activating the developer mode. But I have to confess that this issue doesn't bother me too much, I have many more serious problems to solve :-)