Grid Size adjustment shortcuts don't functions in blueprints

When the shortcuts for "Grid Size(Position):Decrement/Increment" ( '[' and ']' by default) are used in the main viewport editor, the grid size for a blueprint's viewport are updated as well.

However the shortcut keys have no effect when used in the blueprint viewport. No change is made to blueprint / main viewport grid size.

Regression:
No - same behavior occurs in 4.16.3 (CL 3561208)

1. Open UE4 Editor (any project)
2. Create a blueprint based on Actor
3. Click in the main viewport and press ] a couple times
   • Notice the grid snap size updates in the main viewport and blueprint viewport
4. Repeat previous step in blueprint viewport

Result:
When the blueprint viewport has focus, the shortcut keys have no effect

Expected:
Grid Size shortcut keys update blueprint / main grid when pressed.