wasm: standardContextMenu is not shown

While comparing the latest v6.9.0 release on WebAssembly platform, I have noticed that the context menu does not appear anymore. 

Reproducing the issue:

(
Compile scripts: https://hyperborg.com/cp/bugreport.tar.gz 
main.cpp only: https://hyperborg.com/cp/main.cpp)

• • • v6.8.2 --*
      Go to: https://hyperborg.com/cp/v6.8.2/copypaste.html 
      press right click and the context menu appears

• • • v6.9.0--*
      When using the same source code, but Qt v6.9.0 for WASM, the context menu does not show. 
      Go to: https://hyperborg.com/cp/v6.9.0/copypaste.html
      Right click on the QTextEdit area, but nothing happens.