http://superuser.com/questions/355915/vista-dpi-scaling-cannot-disable-dpi-scaling-for-wireshark/355953#355953?s=97656833-4e08-4a55-8773-1fe68b5fca77
Brief instructons.
Go to HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers Most likely you'll already see a setting for 32-bit Rgui.exe Make a similar one by right clicking on the "Layer" and add new string value. Name: C:\Program Files\R\R-3.0.2\bin\x64\Rgui.exe Type: REG_SZ Data: HIGHDPIAWARE