Start IntelliJ's "Empty Diff" via CLI

Question

I currently use the cool feature via cli to diff two files:

$> idea diff File1 File2

But another cool tool is in IntelliJ to "Open blank diff window" (via find Action).

But when I run

$> idea diff

The IDE closed it directly.

Has anybody an Idea how I can directly start the Open empty diff via CLI? Thanks!