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.

Steps to Reproduce

1. Click a button using touch on a touch monitor.

Result: Button is clicked twice.
Expected Result: Button is clicked once.

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ComponentUE - Editor - UI Systems - Slate
Affects Versions4.14
Target Fix4.17
Fix Commit3484703
Main Commit3499771
CreatedMar 22, 2017
ResolvedJun 12, 2017
UpdatedApr 27, 2018
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