HTML-5 mouse UI input not recognized

In Unreal 4.13.2, using Chrome/Firefox, when launching any game, mouse input is not recognized when clicking anywhere on the game’s screen. unless I resize the browser to a smaller size, forcing it to full rescale the content.

After rescaling, I can get the UI buttons to be clickable again. On current APP, we have highlight when mouse cursor is over an UI element and until resize, the UI elements never register.

This was working fine on 4.12 - is there something that has changed with 4.13 that requires setting the mouse input on start differently?

Hello chalde,

I was able to reproduce this issue on our end. I have written up a report and I have submitted it to the developers for further consideration. I have also provided a link to the public tracker. Please feel free to use the public tracker for future updates. Thank you for your time and information.

Link: Unreal Engine Issues and Bug Tracker (UE-38410)

Make it a great day

Extenuating information:

Check out a new WebAssembly + WebGL 2 demo of UE4 at

That demo incorporates a number of the upcoming fixes, and mouse and resizing should work properly.