Some Button OnClicked Not Responding When Focus On A Editable Text

Hey guys, my title may be somewhat confusing as the question I confronted with.

The problem is when my focus is on a EditableText and I click some Button else where, some of the buttons won’t trigger the OnClicked event. I follow the code in function FSlateApplication::RoutePointerDownEvent only to find nothing actually useful.

However, what can temporarily solve my problem is to uncheck the check box of IsFocusable of the button in editor. That is to say, if a button is not focusable, then I can trigger the OnClick event when my focus is in a EditableText. But with those focusable button, the event won’t get called.

I’ve spent about a day on this question and made little progress. I am new to UE4 and unfamiliar with how UE4 “route” the click event. Despite I have a temporary solution, I want to know what is the real cause of this question. By the way, I don’t want to set every button as not focusable if this is not what the engine intends the user to do so. So I come to here and ask for help.

some of the buttons won’t trigger the
OnClicked event

What’s special about some them? Under regular circumstances, the focus seems to be shifting correctly:

Image from Gyazo