Because individual movie clips and objects in a Generator template can have their own data sources assigned to them, a Generator template typically contains multiple data sources.
When a Generator template has several data sources assigned to it, Generator searches each data source for variables and the values to assign them. The search starts with command-line parameters, followed by the main movie's timeline data source assigned using the Generator Environment Variable button, and then any data sources assigned to child Generator objects and movie clip timelines.
If variables with the same name are assigned different values in data sources specified for child timelines of symbols, the new value overwrites the older value defined in parent timelines or the command line (or URL query string). If a child timeline doesn't redefine a variable, the variable inherits its value from any parent timelines or the command line. If the variable is not declared in any timeline and is not passed on the command line or URL, the variable is left with no value assigned (or a blank value). At the end of this process, any variables that have not been assigned values are left blank, except action variables, which remain unchanged.
Be aware that scenes are an extension of the main timeline and are not preserved as distinct imelines in the final exported Flash Player movie or Generator template. Any variables that are not unique across scenes will be redefined using the last declaration found, which will apply to that variable for all scenes in the movie.