Tested with computers Compaq Deskpro EN (Windows 2000 prof) and HP D530 (Windows XP prof) both with 1280x1024 screen resolution acting as VNC servers.
TightVNC version: 2.7.10 32bit
DFMirage driver version: 2.0.301
TightVNC Server is always using the Mirage Driver when available. The configuration "Use mirror driver if available" setting is ingnored. So the only possible way to prevent TightVNC Server from using the Mirage Driver is to uninstall the driver.
When typing something in Notepad the cursor position gets updated, but the viewer screen right before the cursor is not. So it looks like nothing was typed in. It is necesary to force the screen refresh, for the typed in text to show up. In order to get rid of the problem it was necesary to uninstall the DFMirage driver. The problem shows with both TightVNC and UltraVNC 1.0.2 viewers.