It think I found a bug;
When I want to upload/select a file from within a Web Page the Browse screen wont show.
Click on Choose File and nothing happens.
thx for the report! This will be supported in the next beta version of the WebKit plugin for Royal TSX V4.
If you're not using the beta yet you can get it here: https://www.royalapplications.com/ts/mac/features-beta