The MSHTML option setting MiscFlags sets a few aspects of behaviour, mostly for when MSHTML provides HTML editing services.

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Settings
Value MiscFlags
Type REG_BINARY (4 bytes) or REG_DWORD
Default zero (as dword)

The key shown in the table is only where MSHTML looks for the value ordinarily. If the document host specifies an option key (through the GetOptionKeyPath method of the IDocHostUIHandler interface), then the value is sought instead from the Settings subkey of the option key. If the document host specifies an override key (through the GetOverrideKeyPath method of the IDocHostUIHandler2 interface), then if the value is given in the Settings subkey of the override key, it has precedence.

The value is read either as a dword or as 4 bytes of binary data, and is interpreted as bit flags:

0x01 do not show aligned site tags
0x02 do not show script tags
0x04 do not show comment tags
0x08 do not show style tags
0x10 do not show area tags
0x20 do not show unknown tags
0x40 do not show miscellaneous tags
0x80 do not show zero border at design time
0x0100 do not activate normal OLE controls
0x0200 do not activate design-time controls
0x0400 do not activate Java applets
0x0800 do not show BR tags

The 0x01, 0x04, 0x08, 0x10, 0x20, 0x40 and 0x0800 flags assume an editing context. If any is set before MSHTML has yet prepared an editing context for the document, then a coding error causes MSHTML to dereference a null pointer. These flags look like they may be unusable.