Select Delete Collection in the Collection menu to permanently delete the current collection. The collection will be closed and its file deleted. The file will be placed in the Windows Recycle Bin (if stored on a hard disk or drive with a Windows Recycle Bin). The clips will not be placed in the AceText Recycle Bin.
There is no toolbar button for the Delete Collection command. If you've hidden the main menu, you can access the command by right-clicking on a collection's tab.