Default RNA SS to 'matching bracket' for manual entry

Right-click on annotation and choose 'RNA Helix' to enter symbols - the offered default is a lower-case sigma.
a) this is an odd default as not a recognised rna SS symbol
b) would it be user-friendly to populate with either '(', or the closing bracket symbol to match the nearest unpaired opener (if any)

Note also: the pop-up menu appears (on right-click) even if no columns are selected, but the action is performed on the selection i.e. nothing happens. Would it be better to only show the menu if there is a selection?