Script folders can be configured in Eclipse Preferences -> Groovy -> Compiler preference page:
Several script folders are included by default, which can be changed if required. Each entry is a regular expression that captures a set of Groovy files to be treated as scripts. The syntax of these regular expressions are similar to the syntax of Apache Ant patternSets. By default, script folders are disabled workspace-wide. Uncheck the "Disable script folders..." check box to enable them.
Groovy scripts are designated in the Package Explorer and in the Editor through a variant of the groovy icon in the Package Explorer:
and in the Editor
The 2.1.0 final release is scheduled for a week from now to coincide with the 2.5.0 release of the SpringSource Tool Suite before SpringOne 2GX in October. Because this version is a release candidate, only critical bug fixes will be made between now and the final release.