It seems impossible to shell a help-file-document using OS_Shell.
If it were possible to shell in ASync-mode then i would have some process-ID.

Just there is no way to check if the process with the given ID is still running since OS_ProcessIsRunning() awaits a process-name.

It works to use this for example:
Uses "OS"
' thinBasic-InstallPath has to be "C:\thinBasic\" for this

OS_ShellExecute("open", "thinBasic.chm", "", "C:\thinBasic\Help", %SW_SHOWNORMAL )
but this does not return any process-ID

How can i determine now if this help-file is already|still open (so not to open another one) ?
And how can i close it again when my script ends?