In all cases the Jenkins Groovy editors are limited. No, I am not asking for more features for the editor itself, but it occurs to me that a fairly simple enhancement to all of these interfaces could make it very easy to hop in/out of your favorite Groovy Editor; Mine is Netbeans.
Like most editors, Netbeans monitors the disk to notice if the file has been changed outside the editor.
So if Script Console for instance would after 5 seconds of no typing, save the file to %JENKINS_HOME%/GroovyScript/ScriptConsole.groovy (or whatever) ... I could then stop typing and almost immediately have the current script in Netbeans (assuming Netbeans currently had that file open). Similarly then, once I finish all my auto-tab, intellisensed changes in Netbeans, I hit "save" and the Groovy Console could then pull back in my changes and I could run them. I could easily make changes in either editor as was most convenient and jump back and forth without all the usual copy/paste nonsense.
Script Console could even offer the previous script back on the start of a new session.
Groovy Postbuild has the additional issue that Postbuild is on a job by job basis, so it save area might be %JENKINS_HOME%/GroovyScript/%ITEM_ROOTDIR.groovy. (The name isn't important, but you get the idea).
Scriptler in a sense already has the files saved, but in an XML file with lots of other metadata that gets in the way. It might save a "clean" version of the groovy in %JENKINS_HOME%/GroovyScript/Scripter.groovy. It would not need to offer all the scripts this way . . . only the script currently being edited.