Can't open diff application

[ykuwashima]

Hi.

I using Yummy FTP Pro 1.11.8.

When override remote file, Yummy FTP is show confirmation dialog with show diff button.
But this button is not available in my MBP.

Show this dialog https://www.anony.ws/image/JeBL.
(It's mean "Can't open file. AirPlayUIAgent is not supported PHP script file.")

I set diff application to kdiff3 http://kdiff3.sourceforge.net/.

How this features are available?

[JD]

The app isn't a native Mac app so it doesn't accept basic things like the standard Open Documents message (AppleEvent) which all other apps support. There is no way to fix this, unfortunately - the developer must add support for the Apple standards.

[ykuwashima]

Thank you for your answer.
I set FileMerge.app to diff tool,  showed file differences.