Update: This issue is resolved for me using TeamViewer 12 + Firefox Nightly and/or Google Chrome on Windows 10 build 14986+.
If browser windows such as Mozilla Firefox, Google Chrome, or even BitTorrent Sync’s UI are completely whited out when viewing them remotely on Windows 8.1+, do this on both the host and client PCs:
- Open TeamViewer.
- Click Extras.
- Click Options.
- In the sidebar, click Remote Control.
- Under Display, uncheck Remove remote wallpaper.
- In the sidebar, click Meeting.
- Under Display, uncheck Remove own wallpaper.
- Click OK.
Browser windows should render normally now.