Option to disable twisties for files in the "project explorer" view

JBT extends project explorer view so all files now have twisties near them, even for files that are not expandable (i.e. when you click twistie it just disappears).

It would be nice to have a preference to disable this file "augmentation" or at least for these twisties to be displayed only for files that can really be expanded (faces-config.xml, web.xml, etc.).

Twistie is a little +/- or triangle icon near node of the tree to expand/collapse it. Strange word, but never heard a better name for this GUI element.