I have created a simple splash screen using the Activity Indicator. The splash screen is run on its own thread and message pump. When the application's main form (on the main ui thread) starts initializing the activity indicator stops running, but the debugger shows it is still in the Enabled state. The splash screen itself is fully responsive. I added a WinForms progress bar to the splash screen in addition to the ActivityIndicator and the progress bar continues running throughout, as expected.
Adding a button to the splash screen to test calling Start() on the Activity indicator did not work (which is reasonable if the ActivityIndicator already thinks it is enabled). Calling Stop() and then Start() in succession from this button handler will get the activity indicator running again.
I have not been able to reproduce this issue when running the splash screen against a smaller sample project. I am not referencing the activity indicator anywhere else but in designer code (it is enabled and stop is never called on it).
Has anyone else seen the ActivityIndicator predictably stop running for no reason?