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If you add a throbber to a UMG Blueprint and use the Graph of the Blueprint to change the 'Set Number of Pieces' and use 'Event Tick' to tick the widget, the throbber widget will not appear on screen when PIE.
Photo has been attached to show Graph setup within the Widget.
1) Open a new first person template project
2) When the project opens, Right click in the Content Browser to create a new Widget Blueprint
3) Name the widget and then double click to open
4) Once open, Add a throbber to the UMG window
5) Do not change any of the Details of the Throbber
6) Open the graph of the graph of the UMG
7) Setup the Graph as shown in the Photo Attached
8) Compile and Save the Widget
9) Close the Widget
10) Use the Level Blueprint to add the Widget to the level (photo attached)
11) Save all and then Play in Editor
12) You should see no throbber on the screen
13) If you switch to Event Construct, the widget will show
Head over to the existing Questions & Answers thread and let us know what's up.