The new Java FX Script Plugin for Netbeans was greatly improved. Code completion (with strg+space) is supported now. It can be still improved in detail (e.g. the suggestions for attribute types etc. are not realized yet), but it already provides great simplification. Even methods from imported Java-classes are suggested.
Because I still haven't memorized all Java FX Script keywords, it speeds up significantly the coding - im working now on a UI for greenfire.
This plugin can be downloaded from the Netbeans Beta Update. The installation is described here.