This issue has been closed as 'Won't Fix' due to an extended period of time without updates. If this issue is important to you please let us know by posting on the AnswerHub or UDN, and Epic will re-open the ticket for further review.
Toggling game view does not hide icons/assets in viewports outside of perspective view that would not be visible in game mode.
Regression (No) issue (does) occur in 4.10.4
Results
Game icons do not get removed from the editor viewport
Expected
Game icons that would not be seen in play are hidden from viewport.
Head over to the existing Questions & Answers thread and let us know what's up.