The problem is that windows supplies both a touch event and a mouse event for each touch. The engine then handles touches as mouse input so that UI elements can work correctly on touch platforms.
1. Click a button using touch on a touch monitor.
Result: Button is clicked twice.
Expected Result: Button is clicked once.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-43213 in the post.
| 52 |
| Component | UE - Editor - UI Systems - Slate |
|---|---|
| Affects Versions | 4.14 |
| Target Fix | 4.17 |
| Fix Commit | 3484703 |
|---|---|
| Main Commit | 3499771 |
| Created | Mar 22, 2017 |
|---|---|
| Resolved | Jun 12, 2017 |
| Updated | Apr 27, 2018 |
| 3443 - IlinAleksey |
| 3448 - IlinAleksey |