WARNING: the secondary structure parser in RnaViz is somewhat pickier about the location of helix numbers in the DCSE alignment format than versions of DCSE <4, eg. the helix number must always come on a position after the helix opening symbol ([) in a sequence.
When the source does contain more than one sequence, RnaViz will show a list with the names of the sequences in the file, and you can choose which have to be drawn. If you select more than one structure to be drawn, another dialog with 2 options will pop up. This will let you select wether all selected structures are drawn on the same page (Load selected structures on current page) or each structure is made on a seperate page, and saved to a different file. In the latter case RnaViz will prompt for a filename on which the names for these files will be based.