I just notice a strange behavior that took me some time to trace back: if you activate Project Settings/Input/Always Show Touch Interface, you won’t be able to interact with any of your UMG widgets, including textbox and button, wherever they are on the screen. Changing the priority or Zorder of the widget did not change anything.
Presumably, this is due to the fact that Touch Interface is shown with UMG and with the highest priorities ? Which could be logical for the area involved with the Touch Interface, but it actually cover all the frame.
- from a blank project, create a GameMode + Controller + Pawn + basic UMG with a textbox and button
- assign the Controller & Pawn in the GameMode, and inside the Pawn, Create & Add to viewport the UMG
- inside the UMG, simply SetInputGameAndUI (or SetInputUI only) to the widget + show mouse cursor