Hi again, working on a GUI-only contributed package, the following potential enhancements (for package authors) occur to me: - Add a possibility to mark the return value as mandatory for a GUI function (perhaps only for gui-main). Sometimes a package does nothing else than providing the return value, i.e. no printout, no plots. It would be useful to disallow running the package without filling in the return assignment name. (Currently it's always optional AFAIK.) - Conditional sensitivity: allow to make it dependent on existence, i.e. a non-null value of another parameter. Currently it can only process booleans and scalars, I believe. For example, having an optional series argument and then activating some widgets when that series input is not null would be nice. - Run-time maximum value for integers with drop-down list: An integer can be assigned a max possible value at runtime, at least according to the doc. I have an integer representing a discrete choice, with a labeled drop-down list. (Hope it's clear what I mean.) For example, let's say the choice list according to values 1,2,3 is "ols", "gls", "arma". But arma only makes sense for a time-series dataset. So in the ui-maker function I want to use the $datatype accessor to disallow the integer input value 3 whenever the dataset is not time-series, by setting the maximum allowed value to 2 for that integer. An extra bonus of course would be to grey out the "arma" choice as well, but that's already luxury. I have tested this for my case, but it had no effect. (I guess that's because the maximum value is already hardwired when a drop-down list is given.) thanks, sven