Internet Explorer Options

All the MSHTML Options listed on this page are ordinarily in the following registry key or in some subkey of it:

This ordinary location can be supplanted in various ways. First, a document host may specify so-called option and override keys. Second, though only in recent Windows versions, some options are also supported in policy keys. For interpretation, including the precedence of alternative registry locations, refer to the general discussion.

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value AlwaysAllowExecCommand
Type boolean
Default false
Availability MSHTML.DLL version 6.00 from Windows XP SP2, and higher

The motivation for the AlwaysAllowExecCommand option may be the following difficulty that Microsoft hints at in the HTML and DHTML Reference: “Do not invoke the execCommand method until after the page loads.” The damage that might be risked from ignoring this injunction is unknown. It is known however that the document object’s implementation of this method ordinarily fails, in the sense of causing a runtime script error, if the document does not yet have a window or a sufficiently initialised windowed markup context. The AlwaysAllowExecCommand option defeats these defences.

The AlwaysAllowExecCommand option has no known user-interface support.

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Settings
Value Always Use My Colors
Type boolean
Default false
Availability MSHTML.DLL version 4.71 and higher

The Always Use My Colors option has user-interface support through Internet Properties in the Control Panel, as “Ignore colors specified on webpages” in the Accessiblity dialog (reached from the General tab).

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Settings
Value Always Use My Font Face
Type boolean
Default false
Availability MSHTML.DLL version 4.71 and higher

The Always Use My Font Face option has user-interface support through Internet Properties in the Control Panel, as “Ignore font styles specified on webpages” in the Accessiblity dialog (reached from the General tab).

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Settings
Value Always Use My Font Size
Type boolean
Default false
Availability MSHTML.DLL version 4.71 and higher

The Always Use My Font Size option has user-interface support through Internet Properties in the Control Panel, as “Ignore font sizes specified on webpages” in the Accessiblity dialog (reached from the General tab).

Key HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Settings
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Settings
Value Anchor Color
Type RGB string
Default system colour COLOR_HOTLIGHT if platform is NT and major version ≥ 6;
else 0,0,255
Availability option: MSHTML.DLL version 4.71 and higher
policy: MSHTML.DLL version 7.00 and higher

The default as listed is from inspection of Windows Vista. Windows XP SP1a does not make cases, so that 0,0,255 is the only default.

The Anchor Color option has user-interface support through Internet Properties in the Control Panel, as “Unvisited” in the Colors dialog (reached from the General tab). It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Prevent users from configuring the color of links that have not yet been clicked” in the Link Colors category (itself under “Display settings” and Internet Settings) of the Internet Explorer administrative template (displayed under Windows Components).

This option even has formal documentation: the page Determining the Preferred Hypertext Link Color explicitly directs the setting of this registry value in a document host’s override key.

Key HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Settings
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Settings
Value Anchor Color Hover
Type RGB string
Default 255,0,0
Availability option: MSHTML.DLL version 4.71 and higher
policy: MSHTML.DLL version 7.00 and higher

The default as listed is from inspection of Windows Vista. The default for Windows XP SP1a is 0,0,128.

The Anchor Color Hover option has user-interface support through Internet Properties in the Control Panel, as “Hover” in the Colors dialog (reached from the General tab). It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Prevent users from configuring the hover color” in the Link Colors category (itself under “Display settings” and Internet Settings) of the Internet Explorer administrative template (displayed under Windows Components).

This option even has formal documentation: the page Determining the Preferred Hypertext Link Color explicitly directs the setting of this registry value in a document host’s override key.

Key HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Settings
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Settings
Value Anchor Color Visited
Type RGB string
Default computation from system colours COLOR_WINDOW and COLOR_TEXT if platform is NT and major version ≥ 6;
else 129,0,129
Availability option: MSHTML.DLL version 4.71 and higher
policy: MSHTML.DLL version 7.00 and higher

The default as listed is from inspection of Windows Vista. The computation is to average the red and blue components of COLOR_WINDOW and COLOR_TEXT but take green entirely from COLOR_TEXT. On a typical configuration with black text on white windows, the result is 128,0,128, which is also the default for Windows XP SP1a.

The Anchor Color Visited option has user-interface support through Internet Properties in the Control Panel, as “Visited” in the Colors dialog (reached from the General tab). It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Prevent users from configuring the color of links that have already been clicked” in the Link Colors category (itself under “Display settings” and Internet Settings) of the Internet Explorer administrative template (displayed under Windows Components).

This option even has formal documentation: the page Determining the Preferred Hypertext Link Color explicitly directs the setting of this registry value in a document host’s override key.

Key HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Anchor Underline
Type string;
case-insensitive no, yes or hover;
anything else treated as yes
Default yes
Availability option: MSHTML.DLL version 4.71 and higher
policy: MSHTML.DLL version 7.00 and higher

The Anchor Underline option has user-interface support through Internet Properties in the Control Panel, as “Underline links” in the Browsing group on the Advanced tab. It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Turn off configuring underline links” in the Browsing category (itself under “Advanced settings” and Internet Settings) of the Internet Explorer administrative template (displayed under Windows Components). In both user interfaces, the alternatives Always, Hover and Never translate as yes, hover and no.

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International
Value AutoDetect
Type boolean
Default false
Availability MSHTML.DLL version 5.00 and higher

The AutoDetect option has no known user-interface support.

Key HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Settings
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Settings
Value Background Color
Type RGB string
Default system colour COLOR_WINDOW
Availability option: MSHTML.DLL version 4.71 and higher
policy: MSHTML.DLL version 7.00 and higher

MSHTML ignores this option if Use_DlgBox_Colors is true, which it is by default.

The Background Color option has user-interface support through Internet Properties in the Control Panel, as “Background” in the Colors dialog (reached from the General tab). It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Prevent users from configuring background color” in the General Colors category (itself under “Display settings” and Internet Settings) of the Internet Explorer administrative template (displayed under Windows Components).

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Cleanup HTCs
Type boolean
Default false
Availability MSHTML.DLL version 6.00 from Windows XP SP1a, and higher

The Cleanup HTCs option has no known user-interface support.

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value CSS_Compat
Type string;
case-insensitive never or always;
anything else treated as neither
Default neither
Availability MSHTML.DLL version 6.00 and higher

No string is defined explicitly for the default. A possibly reasonable interpretation, consistent with other registry settings, might be “auto”.

The CSS_Compat option has no known user-interface support.

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International
Value Default_CodePage
Type REG_BINARY, for dword
Default TO BE DONE
Availability MSHTML.DLL version 4.71 and higher

This option is left at its default by MSHTML’s handling of a settings-change notification.

The Default_CodePage option has user-interface support from INETCPL but only through an old-style Fonts dialog that can be invoked programmatically by calling the exported function OpenFontsDialog.

Key HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\International\Scripts
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\Scripts
Value Default_IEFontSize
Type REG_BINARY for byte, REG_DWORD for word;
coerced to 0 to 4 inclusive
Default TO BE DONE
Availability option: MSHTML.DLL version 5.00 and higher
policy: MSHTML.DLL version 7.00 and higher

The Default_IEFontSize option has no known user-interface support.

Key HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\International\Scripts
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\Scripts
Value Default_IEFontSizePrivate
Type REG_BINARY for byte, REG_DWORD for word;
coerced to 0 to 4 inclusive
Default TO BE DONE
Availability MSHTML.DLL version 7.00 and higher

The Default_IEFontSizePrivate option has no known user-interface support.

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Disable_Local_Machine_Navigate
Type boolean
Default true
Availability MSHTML.DLL version 6.00 from Windows XP SP1a, and higher

The Disable_Local_Machine_Navigate option has no known user-interface support.

Key HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Disable Script Debugger
Type boolean
Default true
Availability option: MSHTML.DLL version 4.71 and higher
policy: MSHTML.DLL version 7.00 and higher

This option is left at its default by MSHTML’s handling of a settings-change notification.

The Disable Script Debugger option has user-interface support through Internet Properties in the Control Panel, as “Disable script debugging (Other)” in the Browsing group on the Advanced tab. It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Turn on script debugging” in the Browsing category (itself under “Advanced settings” and Internet Settings) of the Internet Explorer administrative template (displayed under Windows Components).

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value DisableScriptDebuggerIE
Type boolean
Default true
Availability MSHTML.DLL version 6.00 from Windows XP SP2, and higher

This option is left at its default by MSHTML’s handling of a settings-change notification.

The DisableScriptDebuggerIE option has user-interface support through Internet Properties in the Control Panel, as “Disable script debugging (Internet Explorer)” in the Browsing group on the Advanced tab.

Key HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Display Inline Images
Type boolean
Default true
Availability option: MSHTML.DLL version 4.71 and higher
policy: MSHTML.DLL version 7.00 and higher

The Display Inline Images option has user-interface support through Internet Properties in the Control Panel, as “Show pictures” in the Multimedia group on the Advanced tab. It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Turn off picture display” in the Multimedia category (itself under “Advanced settings” and Internet Settings) of the Internet Explorer administrative template (displayed under Windows Components).

Key HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Display Inline Videos
Type boolean
Default true
Availability MSHTML.DLL version 4.71 and higher
policy: MSHTML.DLL version 6.00 from Windows Server 2003 SP1, and higher

As a policy, the Display Inline Images option has user-interface support in the Group Policy Object Editor, as “Play videos in web pages” in the Advanced Page category (itself under Internet Control Panel) of the Internet Explorer administrative template (displayed under Windows Components).

Key HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Enable AutoImageResize
Type boolean
Default true
Availability option: MSHTML.DLL version 6.00 and higher
policy: MSHTML.DLL version 7.00 and higher

The Enable AutoImageResize option has user-interface support through Internet Properties in the Control Panel, as “Enable automatic image resizing” in the Multimedia group on the Advanced tab. It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Turn off automatic image resizing” in the Multimedia category (itself under “Advanced settings” and Internet Settings) of the Internet Explorer administrative template (displayed under Windows Components).

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Expand Alt Text
Type boolean
Default false
Availability MSHTML.DLL version 4.71 and higher

The Expand Alt Text option has user-interface support through Internet Properties in the Control Panel, as “Always expand alt text for images” in the Accessibility group on the Advanced tab.

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Force Offscreen Composition
Type boolean
Default false
Availability MSHTML.DLL version 5.50 from Internet Explorer 5.5 SP2, and higher

The Force Offscreen Composition option has user-interface support through Internet Properties in the Control Panel, as “Force offscreen compositing even under Terminal Server” in the Browsing group on the Advanced tab.

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Styles
Value MaxScriptStatements
Type dword
Default 5 million
Availability MSHTML.DLL version 4.71 and higher

The MaxScriptStatements option has no known user-interface support.

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Settings
Value MiscFlags
Type dword
Default zero
Availability MSHTML.DLL version 4.71 and higher

This option is left at its default by MSHTML’s handling of a settings-change notification.

The MiscFlags option has no known user-interface support.

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Move System Caret
Type boolean
Default false
Availability MSHTML.DLL version 4.72 and higher

The Move System Caret option has user-interface support through Internet Properties in the Control Panel, as “Move system caret with focus/selection changes” in the Accessibility group on the Advanced tab.

Key HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Page_Transitions
Type boolean
Default true
Availability option: MSHTML.DLL version 5.50 and higher
policy: MSHTML.DLL version 7.00 and higher

The Page_Transitions option has user-interface support through Internet Properties in the Control Panel, as “Enable page transitions” in the Browsing group on the Advanced tab. It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Turn off page transitions” in the Browsing category (itself under “Advanced settings” and Internet Settings) of the Internet Explorer administrative template (displayed under Windows Components).

Key HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Play_Animations
Type boolean
Default true
Availability option: MSHTML.DLL version 4.71 and higher
policy: MSHTML.DLL version 6.00 from Windows Server 2003 SP1, and higher

The Play_Animations option has user-interface support through Internet Properties in the Control Panel, as “Play animations in webpages” in the Multimedia group on the Advanced tab. It has user-interface support as a policy, too, through the Group Policy Object Editor, with the same description, in the Advanced Page category (itself under Internet Control Panel) of the Internet Explorer administrative template (displayed under Windows Components).

Key HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Play_Background_Sounds
Type boolean
Default true
Availability option: MSHTML.DLL version 4.71 and higher
policy: MSHTML.DLL version 6.00 from Windows Server 2003 SP1, and higher

The Play_Background_Sounds option has user-interface support through Internet Properties in the Control Panel, as “Play sounds in webpages” in the Multimedia group on the Advanced tab. It has user-interface support as a policy, too, through the Group Policy Object Editor, with the same description, in the Advanced Page category (itself under Internet Control Panel) of the Internet Explorer administrative template (displayed under Windows Components).

Key HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Print_Background
Type boolean
Default false
Availability option: MSHTML.DLL version 4.71 and higher
policy: MSHTML.DLL version 7.00 and higher

The Print_Background option has user-interface support through Internet Properties in the Control Panel, as “Print background colors and images” in the Printing group on the Advanced tab. It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Allow the printing of background colors and images” in the Printing category (itself under “Advanced settings” and Internet Settings) of the Internet Explorer administrative template (displayed under Windows Components).

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Q051873
Type boolean
Default false
Availability MSHTML.DLL version 6.00 (only)

The Q051873 option has no known user-interface support.

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Q300829
Type boolean
Default false
Availability MSHTML.DLL version 6.00 from Windows XP SP1, and higher

The Q300829 option has no known-user interface support but does have documentation. According to the Microsoft Knowledge Base article Cannot Edit Content in Frames or Iframes in DHTML, this option enables a fix which Microsoft documents as having been introduced for Internet Explorer 5.5 SP2 and Internet Explorer 6 SP1. However, inspection of an MSHTML version 5.50.4807.2300 from Internet Explorer 5.5 SP2 shows no sign of support.

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Q331869
Type boolean
Default false
Availability MSHTML.DLL version 6.00 from Windows XP SP2, and higher

The Q331869 option has no known user-interface support but does have documentation. According to the Microsoft Knowledge Base article The OnBeforeUnload and OnUnload Events Are Not Triggered in Internet Explorer 6 SP1 If the Body Tag Is Empty, this option enables a fix which Microsoft documents as having been introduced in a patched version of MSHTML that was released slightly after Internet Explorer 6 SP1. Among releases of MSHTML that were distributed with Windows, this option appears first in Windows XP SP2.

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer
Value RtfConverterFlags
Type dword
Default 0x00000001
Availability MSHTML.DLL version 4.71 and higher

The RtfConverterFlags option has no known user-interface support.

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer
Value Show_FullURL
Type boolean
Default false
Availability MSHTML.DLL version 4.71 up to but not including 7.00

The Show_FullURL option has user-interface support through Internet Properties in the Control Panel, as “Show Friendly URLs” in the Browsing group on the Advanced tab.

Key HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Show image placeholders
Type boolean
Default false
Availability option: MSHTML.DLL version 5.00 and higher
policy: MSHTML.DLL version 7.00 and higher

The Show image placeholders option has user-interface support through Internet Properties in the Control Panel, as “Show image download placeholders” in the Multimedia group on the Advanced tab. It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Allow the display of image download placeholders” in the Multimedia category (itself under “Advanced settings” and Internet Settings) of the Internet Explorer administrative template (displayed under Windows Components).

Key HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Internet Explorer
HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer
Value SmartDithering
Type boolean
Default true
Availability option: MSHTML.DLL version 4.71 and higher
policy: MSHTML.DLL version 7.00 and higher

The SmartDithering option has user-interface support through Internet Properties in the Control Panel, as “Smart image dithering” in the Multimedia group on the Advanced tab. It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Turn off smart image dithering” in the Multimedia category (itself under “Advanced settings” and Internet Settings) of the Internet Explorer administrative template (displayed under Windows Components).

Key HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Smoothscroll
Type boolean
Default true
Availability option: MSHTML.DLL version 4.71 and higher
policy: MSHTML.DLL version 7.00 and higher

The Smoothscroll option has user-interface support through Internet Properties in the Control Panel, as “Use smooth scrolling” in the Browsing group on the Advanced tab. It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Turn off smooth scrolling” in the Browsing category (itself under “Advanced settings” and Internet Settings) of the Internet Explorer administrative template (displayed under Windows Components).

Key HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Settings
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Settings
Value Text Color
Type RGB string
Default system colour COLOR_TEXT
Availability option: MSHTML.DLL version 4.71 and higher
policy: MSHTML.DLL version 7.00 and higher

MSHTML ignores this option if Use_DlgBox_Colors is true, which it is by default.

The Text Color option has user-interface support through Internet Properties in the Control Panel, as “Text” in the Colors dialog (reached from the General tab). It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Prevent users from configuring the text color” in the General Colors category (itself under “Display settings” and Internet Settings) of the Internet Explorer administrative template (displayed under Windows Components).

Key HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Internet Explorer\Settings
HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Settings
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Settings
Value Use Anchor Hover Color
Type boolean
Default false
Availability option: MSHTML.DLL version 4.71 and higher
policy: MSHTML.DLL version 7.00 and higher

The Use Anchor Hover Color option has user-interface support through Internet Properties in the Control Panel, as “Use hover color” in the Colors dialog (reached from the General tab). It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Turn on the hover color option” in the Link Colors category (itself under “Display settings” and Internet Settings) of the Internet Explorer administrative template (displayed under Windows Components).

Key HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value UseClearType
Type boolean
Default false
Availability MSHTML.DLL version 7.00 and higher

The UseClearType option has user-interface support through Internet Properties in the Control Panel, as “Always use ClearType for HTML” in the Multimedia group on the Advanced tab. It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Turn off ClearType” in the Advanced Page category (itself under Internet Control Panel) of the Internet Explorer administrative template (displayed under Windows Components).

Key HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Use_DlgBox_Colors
Type boolean
Default true
Availability option: MSHTML.DLL version 4.71 and higher
policy: MSHTML.DLL version 7.00 and higher

When Use_DlgBox_Colors is true, MSHTML ignores both the Background Color and Text Color options.

The Use_DlgBox_Colors option has user-interface support through Internet Properties in the Control Panel, as “Use Windows colors” in the Colors dialog (reached from the General tab). It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Prevent the use of Windows colors” in the General Colors category (itself under “Display settings” and Internet Settings) of the Internet Explorer administrative template (displayed under Windows Components).

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value UseHR
Type boolean
Default false
Availability MSHTML.DLL version 6.00 and higher

The UseHR option has no known user-interface support but does have documentation. A page titled Adjusting Scale for Higher DPI Screens explicitly directs the setting of this registry value. No mention is made of susceptibility to a document host’s option key or override key.

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Styles
Value Use My Stylesheet
Type boolean
Default false
Availability MSHTML.DLL version 4.71 and higher

The Use My Stylesheet option has user-interface support through Internet Properties in the Control Panel, as “Format documents using my style sheet” in the Accessibility dialog (reached from the General tab).

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Styles
Value User Stylesheet
Type REG_SZ
Availability MSHTML.DLL version 4.71 and higher

This option is ignored unless Use My Stylesheet is true.

The User Stylesheet option has user-interface support through Internet Properties in the Control Panel, as the “Style sheet” edit box and related Browse button in the Accessibility dialog (reached from the General tab).

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value Use Stylesheets
Type boolean
Default true
Availability MSHTML.DLL version 4.71 and higher

The Use Stylesheets option has no known user-interface support.

Key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value UseThemes
Type boolean
Default true
Availability MSHTML.DLL version 6.00 and higher

If MSHTML runs in a process that does not contain a module named either EXPLORER.EXE or IEXPLORE.EXE, it overrides UseThemes from the registry, forcing false.

The UseThemes option has user-interface support through Internet Properties in the Control Panel, as “Enable visual styles on buttons and controls in web pages” in the Browsing group on the Advanced tab.

Key HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Main
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
Value XMLHTTP
Type boolean
Default true
Availability MSHTML.DLL version 7.00 and higher

The XMLHTTP option has user-interface support through Internet Properties in the Control Panel, as “Enable native XMLHTTP support” in the Security group on the Advanced tab. It has user-interface support as a policy, too, through the Group Policy Object Editor, as “Enable Native XMLHttp Support” in the Security Features category of the Internet Explorer administrative template (displayed under Windows Components).