Runs Sensitivity to all with the setup held by the Sensitivity to all tool: the variables and settings from its dialog. As with MENU>RUN, the option O (the letter oh) overwrites an existing run of the same name without asking.
The action recorder writes this command when you run the tool, so a recorded script can repeat the run in the same session. A script started in a fresh copy of Vensim has no setup for it to use. The command is not available in the Vensim DLL.
