1. Should be single folding for start and end parts, text between them should be editable, unfold action inside this text should expand both folded regions - Peter Gromov

2. Three nested folding levels: one from 'new' to the method body start, another for starting and ending \n's if method can be formatted as single line, and finally the third will remove 'return' and semicolon as in Function examples - Peter Gromov

3. Unfold keyboard action should unfold these nested levels one-by-one, fold action - to fold as deep as possible given that the caret should still be in unfolded region - Peter Gromov

4. Minus sign on the left should fold/unfold everything; there should be only one plus/minus sign for all levels, placed at the first line of anonymous class - Peter Gromov

5. WriteCommandAction should be folded as well: don't know how to represent its constructor arguments, which are always present - Peter Gromov

6. Usages should be highlighted in folded text: of created class, of method parameters and their types. Ideally also in-place rename - Peter Gromov

7. On breakpoint setting the region should be unfolded completely to make it clear, where the breakpoint is located - Peter Gromov

8. On structure change (e.g. inserting '{') the collapsedness state should be preserved - Peter Gromov

First, it's up to date. Second, current code folding API isn't rich enough to implement some of the features, it will be probably expanded a little. Third, core is better than plugin. Finally, was it really completely the same, with all those lambdas? - Peter Gromov

I know. I read this boilerplate code much more often than write. And IDEA helps me writing it (sadly, causing much more boilerplate code to appear) - Peter Gromov