Regression: Multimedia Widget Media Player Example file dialog issue with WASM

With the Multimedia Media Player Example (Widgets implementation), it is not possible to open files because the file dialog is empty and without controls. 'x' button does not work.

This is a regression from 6.6.1

To reproduce:
1. Run Media Player Example (the Widget based implementation)
2. Push "Open" button

Expected results:
2. File dialog shows up and it is possible to view file system

Actual behavior:
2. A gray rectangle is displayed on screen

Tested with Edge, Firefox and Chrome.
Windows 11
Emscripten 3.1.37