Mouse controller

I’ve created a custom PlayerController with mouse click events enabled, but I need to double-click on an actor before its OnClicked event is fired.
What’s up with this?

This is something to do with the Capture option under Project Settings / Input

If i set the Default Viewport Mouse Capture Mode to “Capture during mouse down” then it works ok. But if it is set to “Capture permanently” then it requires double clicks to register a single click.

Can anyone explain this?