How to resolve conflicts in SVN via Merge Tool?

Hello!

I merged branch with trunk in SVN and got the conflict. I set up TortoiseSVN to resolve conflicts via Unreal Editor Merge Tool:

After that I tried to resolve the conflict, but nothing happened. After i press, for example, «Accept Source» button, Unreal Editor saves something and closes, but the conflict remains.

What is the right way to resolve conflicts? Maybe i’m doing it wrong? Or maybe this tool is bugged or somethig like that?

Thanks in advance,
Dmitry.