OK. When you stop a program in the Control tab, generator screen, you can clear the generator so it is definitely cleared.
The typical error here is that one forgets to click "Allow Generator Overwrite" prior to clicking the generator box when entering the Control tab.
The process is to go to Presets tab, choose either a loaded Preset or a Shell Preset.
If using a Shell Preset, go to Programs tab to load the programs desired.
Go to Control tab, click "Allow Generator Overwrite", then the generator box, the Preset/Program choice should load, then click "Start".
For more details, please check the link: