Jamie: I do have the app set to run on startup. I don't think it's an icon cache issue and rebuilding it looks scary. And, yes, it is a Windows problem, I'm sure, but why does one program work and the other doesn't?
CM630: The App creates one window. It creates two versions observable in Task Manager, even when I remove the shortcut from the Systray. I copied-and-pasted from a program that doesn't behave like this to create the new one. I run and stop ten times, and one doesn't have duplicates, the other always has two. And I'm avoiding Windows 11 and considering Linux Mint.
Hmm, I changed form1's icon to a Bell, the project options icon to a Circle, then I get two incidents of the program in the Systray, both looking like the old icon!!! When I hover over it, the two incidents have left, a Circle, and right, a Bell. Circle does nothing, Bell is the program.
The program's form1 does have the bordericons to false and the borderstyle to bsNone.