Mouse not work on ui at first time

when I packed the application and run, the mouse is not work on any UI, but when I clicked left mouse button,
It works again.
When in editor, there is nothing wrong. All mouse stat and Button work well.

Why it not worl when I packed it to exe ?
How can I do?

Hello,

We’ve recently made a switch to a new bug reporting method using a more structured form. Please visit the link below for more details and report the issue using the new Bug Submission Form. Feel free to continue to use this thread for community discussion around the issue.

https://epicsupport.force.com/unrealengine/s/

Thanks