Using the F key to focus the viewport camera on an actor does not work if the main editor window does not have focus

Using the F key to focus the viewport camera on an actor does not work if the main editor window does not have focus.

Reproduced in 4.8.3 binary, 4.9.1 binary, and Main (CL 2707185)

1. Open any project
2. Drop an actor into the level
3. Move the World Outliner out of the main editor window as a standalone window
4. Select the actor in the World Outliner
5. Hit "F" to focus

Result:
The Viewport camera does not focus on the selected actor because the main editor window does not have focus

Expected:
The Viewport camera focuses on the actor