UMG Widgets not reacting in Standalone, but in Viewport

Hi there…
Following Problem…

We updated to 4.18 from last 4.17… nothing changed on the Blueprints.
Whenever i try to click on specific buttons… they don´t start the OnClicked event. They react for hover and press state and change their Graphics… but don´t start the events.
This only happens in Standalone Testplay…
When i try to run the Game in Selected Viewport, everything works fine…

So… Did i found a Bug… or what is wrong?

4.18 has some bugs… but show your script first…
2 advices:

  1. Try restart editor, it may help
  2. Use print string nodes everywhere, i debugged everything with them, they are pretty useful

There‘s no need for a script screenshot right now…
the setup:
1 User generated Widget as child of a Scrollbox, that is in a Main umg.
inside the widget, a button with an OnClicked Event and a print string linked to it

Testplay in Viewport - printstring is given out by clicking the Button
Testplay in Standalone - printstring is not fired.

the buttons of the parent (main)umg are working. But all child Widgets are not firing their OnClicked, OnPressed or else events.

tries restarting Editor, reinstalling editor and recompiling Project from source. nothing helped.

Pushing this… case this Problem still appears… I´ve completely redone the whole project and i´´m currently thinking it´s a Bug :confused:

Video: - YouTube