Make top level terms un-selectable in hierarchical taxonomy? I have a taxonomy like this:

Color
-blue
-green

Size
-large
-small


I need to use 1 vocabulary not 2. However I need 'Color' and 'Size' to not be selectable. If I create a hierarchal taxonomy is there a way to make certain (the top level) terms un-selectable by nodes?
Using  Hierarchical Select module you can do that and configure it to Force the user to choose a term from deepest level, see the below screenshot.



and also take a look at this Taxonomy Term Reference Tree Widget module, I think it have the option to select only child term and I'm not sure about this module.