With latest pre-release we added the WebView.SetInternetExplorerHiDPI function to switch on the HiDPI aware more for FileMaker application (or runtime). See comparison picture:
In your start script you can just call this function once to enable it:
MBS( "WebView.SetInternetExplorerHiDPI"; 1 )
When this option is active before web viewer is created, the web control will display the content high-dpi aware and zoom to 100% independent of the DPI of the display.
But this is no longer needed on Windows once the web viewer zooms correctly.
PS: For Xojo use IEWebBrowserMBS.SetInternetExplorerHiDPI function to do the same.