That UI appears when the remote control icon in the system tray is double-clicked. It's pretty strange that it's popping up on it's own. Because it's only happening on one computer, it's likely to be a problem with the agent on that computer or the PC itself. As a first step I'd recommend running uninstallwinclient.exe with a /forceclean switch on that computer, and then doing a new agent install. Let us know if the issue persists after that.