(where xxxxx will be different for everyone).
I'm assuming Zone "3" is the "Internet" zone (as seen in InternetExplorer security settings).
There you will either find or need to create a REG_DWORD (32-bit) with the name 1400
Values I know of:
Note: For me, the setting in HKLM had precedence over the setting in HKCU (e.g. changing the setting in HKCU had no effect for me).