Hi,
I have managed to export my desktop application to web using the powerserver toolkit and powerserver. After the export, i wanted to try the application if it works as its desktop version but when i try the application, the datawindows where most of the functions are placed is missing. No error prompts were shown. this application implements the themes feature of pb2019
i have attached a screenshot of the web version and desktop version
But just to clarify, your issue could be caused by other reasons. The UI Themes was just one obvious unsupported feature I noticed.