[R-gui] TclTk dynamic dropdown list combo box

["João G."]

Hi everyone,

I'm trying to build a conditional or dynamic dropdown list that depends 
on a value inserted in a tkentry field. The value in this field will be 
used to subselect a data fame and so defining the values on the 
dependent dropdown list.
This kind of feature is very often found in web based forms, for 
example: selecting a given state fills up a second dropdown that lists 
all the cities in the first option. I'm not sure but probably a button 
should be used to trigger the procedure.
Up to now I've made no progress on doing this since all examples or 
documentation only focus on static dropdowns.

Thanks in advance,
João.