When in the Full Control mode, some special keys (such as Alt, Ctrl or Shift) are not working.
- Update your Viewer and Host to the most recent version. Follow the Updating Remote Utilities guide.
- Make sure the key is not "stuck" (keys stick after being rapidly pressed, it's an accessibility feature). The easiest way to determine whether the key is stuck is to invoke the Windows On-Screen keyboard on the remote PC. The stuck key will be highlighted.
- Close and re-open the Full Control/View Only mode.
- Fully exit the Viewer (File ➝ Exit) and restart the Viewer.