Description:

I'm developing a custom drag system in UMG for a VR/UI project in Unreal Engine 5.4.4. It works perfectly with mouse input, but I'm having issues when using touch input on a mobile device or touchscreen.

How My System Works (Mouse - Fully Functional) I have a main UI widget (WBP_GaleriaGeral) containing a ScrollBox with dynamically generated buttons (WBP_GaleriaIcon).

When I press a button inside the ScrollBox, a new image widget (WBP_ImageDrag) is created at the mouse position and added to the viewport.

Inside WBP_ImageDrag, there is a Tick event that updates the widget’s position to follow the mouse as long as a boolean (AllowDrag) is true.

AllowDrag is set to true in Construct and on Mouse Button Down, and set to false on Mouse Button Up.

Problem with Touch Input When I touch a button (WBP_GaleriaIcon) to create the image widget (WBP_ImageDrag), the first touch always uses the last known mouse position, not the actual touch position.

This means the first spawned WBP_ImageDrag appears in the wrong place, often far from the touch location.

I tried overriding On Touch Started and On Touch Ended to manually set AllowDrag = true/false, just like I do with the mouse, but the issue remains.

After the first touch, dragging works correctly, meaning that Unreal isn't recognizing the new touch input as a position update immediately.

What I Tried (Without Success) Manually setting the mouse position to the touch position right before creating WBP_ImageDrag.

Forcing a "mouse move" event when touch starts.

Using "Convert Screen Location to World Space" to update the position before spawning WBP_ImageDrag.

Calling "Set Input Mode Game and UI" when touch starts.

Checking "Use Mouse for Touch" in Project Settings → Input.

What I Need Help With How can I ensure that the first touch correctly updates the mouse position before spawning the widget?

Is there a way to force Unreal to recognize the touch location immediately upon pressing?

Am I missing a step to properly synchronize touch input and mouse position in UMG?

Thanks in advance for any help!