Ok so, i'm aware that in the registry you can easily "always show all icons in the notification area" or turn this feature off. What I'm looking for is a way to specifically hide or show an applications icon in the notification area. So, this can be done manually by dragging the notification to and from the hidden area and i want to be able to do this through the registry.
What is happening is that i'm installing software that comes with a systray icon, but immediately after installation the systray icon is hidden so i'd like to be able to push a registry edit that unhides it, which would have the same effect as going to Settings > Personalization > Taskbar > Select which icons appear on the task bar > and then clicking the slider next to a specific app to hide or show.
I do NOT want to "Always show all icons in the notification" area because there are some systems that might have a dozen hidden icons for various things and it takes up a significant amount of space on the taskbar.
HKEY_CURRENT_USER\Software\Classes\Local Settings\Software\Microsoft\Windows\CurrentVersion\TrayNotify
. You will see two entries that end with "streams".. I believe that these use an undocumented API to create a crc/hash of "approved to show" applications. It isn't done by exe name or path. To validate my hypothesis (not prove), every time I get an update to an application (like slack or even outlook).. it is no longer shown until I re-add it (due to a different hash). Good luck.