Showing the mouse cursor and holding down the left mouse button while dragging will cause the MouseX event to broadcast incorrect axis values. 

Steps to Reproduce
  • Create a Pawn Blueprint that logs the Axis Value of Event MouseX and set it as the default pawn.
  • Create a PlayerController Blueprint that can toggle bShowMouseCursor and set it as the default player controller.
  • PIE 
  • Smoothly drag the mouse left and right while holding the left mouse button down and notice the axis values are as expected.
  • Toggle bShowMouseCursor via the player controller and repeat the previous step. It may take more than one mouse down event to reproduce, but the axis will start reporting 0.0 every other tick. 

The linked UDN also has a repro project attached that uses a histogram to display the values.

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ComponentUE - Gameplay - Input
Affects Versions4.275.0.1
Target Fix5.3
CreatedMay 11, 2022
UpdatedApr 11, 2023