Steps to reproduce
- Add TrayIcon=0 to the settings file
- Go to Game Mode, set a process to test with, notepad.exe
- Set On Start action to Unload All Skins
- Close the Manage Rainmeter Window
- Rainmeter tray icon remains hidden in the notification tray area when Notepad is open
Some more complicated (usually paid or commercial) Suites usually change the TrayIcon option to be 0 to hide the fact their app works using Rainmeter.
For those who have ventured in Rainmeter though and played with it's settings, they could get in a situation where they have activated Game Mode and left the default setting for the On Start action.
If they add a process name that runs at all time, like conhost.exe or csrss.exe, and close the Manage Rainmeter window, they are now in a situation where the Rainmeter icon is gone and no other way to control the app.
(except command line, but we assume the normal user dosen't know what !RefreshApp is)
(This was found by Orb, over on the Discord server, who hid the normal Rainmeter tray icon using that option in order to use death.crafter's TrayIcon plugin for customized tray icons on his skins)
(I also found out there is no blacklist for the process list so rainmeter.exe crashes Rainmeter, hehe)