Windows 10 setting "Notifications & actions:" Application List is not showing all notification apps

Question

Here's a screenshot of the settings screen for notifications control:

Section "Get notifications from these senders" is displaying some apps.

However there a lot of other apps, showing notifications in actions center, but not being listed in "Get notifications from these senders" list.

Before patch 1607 the notifications data was located on AppDB field of windows registry notifications sections, and later it is located in c:\Users%USERNAME%\AppData\Local\Microsoft\Windows\Notifications\wpndatabase.db, which is SQL lite DB.

This small DB is containing all recent (last 3 days) notifications, notification settings and list of apps which has sent notifications:

As you can see, there are Chrome, Lightshot, some system apps (which has notifications disabled in settings) and two another app named someapp and mywebapp. This two apps can send notifications, which are displayed and can be disabled from toast bar, but they are not listed in the "Get notifications from these senders" list, which makes it quite difficult to re-enable notifications for this apps again - because it involves edit or removal of wpndatabase.db file.

I've tried several tests and found one interesing scenario which seems to prove that wpndatabase.db is not only source of data for the "Get notifications from these senders" list, here's the scenario:

1. Disable notifications for the app in the "Get notifications from these senders" (I've used Lightshot)
2. Stop WPNUserService, delete wpndatabase.db, start WPNUserService
3. Check "Get notifications from these senders" - it is empty now.
4. Get new notification for the app (created new screenshot with Lightshot to make a notification). The notification did not appear, as it is still disabled!
5. Check "Get notifications from these senders" - it has Lightshot in the list, but it is disabled! Means, that wpndatabase.db is not the final source of notification settings.

So, I've started futher search and found that adding 'Enabled' DWORD:32 to Computer\HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Notifications\Settings<Appname> makes wpndatabase.db's HandlerSettings table value s:toast to be set to 0. So it seems like wpndatabase.db is dependend on registry settings. Several additional checks prove that setting 'Enabled' to 0 will result in setting s:toast to 0 on either next notification or Windows Push Notifications User Service restart. However, changing Enabled to 1 or removing it will not have any effect: so it seems like it's some kind of legacy setting, which is taken into account by WPN User Service.

The question is quite simple: why some apps are not listed in the "Get notifications from these senders" section, considering all trivial options are OK (background apps allowed, focus assist is off, notification service is running, and so)

Some other refs: https://www.tenforums.com/tutorials/4111-turn-off-notifications-apps-senders-windows-10-a-5.html https://www.mdpi.com/2673-6756/2/1/7

Mentions of similar problem on web: https://www.tenforums.com/tutorials/4111-turn-off-notifications-apps-senders-windows-10-a.html#post8063

Answer 1

Just after asking question I've found an answer.

It's based on this article: https://learn.microsoft.com/en-us/previous-versions/windows/desktop/legacy/hh802762(v=vs.85)

Without a valid shortcut installed in the Start screen or in All Programs, you cannot raise a toast notification from a desktop app.

When I've created a shortcut for the missing apps in start menu root, the application finally appeared in the "Get notifications from these senders" section.

Seems like this issue is specific for some programs, which use some specific method for raising notification, and this method employs that "AppUserModelID" parameter.

What a weird thing windows is.