Changing a Packaged Game from Fullscreen to Windowed at Runtime Causes Title Bar to Disappear

When changing a packaged game from Fullscreen to Windowed mode at runtime, the window is placed in the top left corner of the monitor and the title bar disappears.

Setting FullscreenMode=2 in the GameUserSetting.ini seems to resolve this issue; however, this is inconsistent with the behavior in 4.11.2.

This issue did not occur in 4.11.2. As a result, it is a regression.

1. Open the editor (First Person BP Project)
2. Open the First Person Character BP
3. Recreate the blueprint in the attached screenshot (It also works if you use Begin Play instead of the 1 key)
4. Compile & Save
5. Package the game for Win64
6. Open the packaged game
7. Press the 3 key

Result: The window becomes stuck in the top left corner of the monitor and the title bar disappears.

Expected: The window would appear centered and would not lose the title bar.

4.13 Preview 1 Repro Steps:

1. Open the attached project
2. Package for Win64
3. Open the game
4. Press 1, 2, and then 3 in that order.

Result: The window becomes stuck in the top left corner and the title bar disappears.

Windowed mode stuck in corner and missing titlebar

Windowed mode stuck in corner and missing titlebar