--- a/layout/reftests/details-summary/reftest.list
+++ b/layout/reftests/details-summary/reftest.list
@@ -1,83 +1,85 @@
+default-preferences pref(dom.details_element.enabled,true)
+
 # Disable <details> and <summary>
 pref(dom.details_element.enabled,false) == single-summary.html disabled-single-summary-ref.html
 pref(dom.details_element.enabled,false) == open-single-summary.html disabled-single-summary-ref.html
 pref(dom.details_element.enabled,false) == no-summary.html disabled-no-summary-ref.html
 
 # Basic <summary> handling
-pref(dom.details_element.enabled,true) == multiple-summary.html single-summary.html
-pref(dom.details_element.enabled,true) == open-multiple-summary.html open-multiple-summary-ref.html
-pref(dom.details_element.enabled,true) == summary-not-first-child.html single-summary.html
-pref(dom.details_element.enabled,true) == open-summary-not-first-child.html open-single-summary.html
-pref(dom.details_element.enabled,true) == open-summary-block-style.html open-summary-block-style-ref.html
-pref(dom.details_element.enabled,true) == no-summary.html no-summary-ref.html
-pref(dom.details_element.enabled,true) == open-no-summary.html open-no-summary-ref.html
-pref(dom.details_element.enabled,true) == summary-not-in-details.html summary-not-in-details-ref.html
-pref(dom.details_element.enabled,true) == summary-not-direct-child.html summary-not-direct-child-ref.html
-pref(dom.details_element.enabled,true) == float-in-summary.html float-in-summary-ref.html
+== multiple-summary.html single-summary.html
+== open-multiple-summary.html open-multiple-summary-ref.html
+== summary-not-first-child.html single-summary.html
+== open-summary-not-first-child.html open-single-summary.html
+== open-summary-block-style.html open-summary-block-style-ref.html
+== no-summary.html no-summary-ref.html
+== open-no-summary.html open-no-summary-ref.html
+== summary-not-in-details.html summary-not-in-details-ref.html
+== summary-not-direct-child.html summary-not-direct-child-ref.html
+== float-in-summary.html float-in-summary-ref.html
 
 # Add elements dynamically
-pref(dom.details_element.enabled,true) == dynamic-add-single-summary.html open-single-summary.html
-pref(dom.details_element.enabled,true) == dynamic-add-summary-not-first-child.html open-single-summary.html
-pref(dom.details_element.enabled,true) == dynamic-add-summary-and-paragraph.html open-single-summary.html
-pref(dom.details_element.enabled,true) == dynamic-add-paragraph-before-summary.html open-single-summary.html
-pref(dom.details_element.enabled,true) == dynamic-add-paragraph-before-summary-close.html single-summary.html
-pref(dom.details_element.enabled,true) == dynamic-add-paragraph-after-summary.html open-single-summary.html
-pref(dom.details_element.enabled,true) == dynamic-add-paragraph-after-summary-close.html single-summary.html
-pref(dom.details_element.enabled,true) == dynamic-add-details.html open-single-summary.html
-pref(dom.details_element.enabled,true) == dynamic-add-first-summary.html open-multiple-summary.html
-pref(dom.details_element.enabled,true) == dynamic-add-second-summary.html open-multiple-summary.html
+== dynamic-add-single-summary.html open-single-summary.html
+== dynamic-add-summary-not-first-child.html open-single-summary.html
+== dynamic-add-summary-and-paragraph.html open-single-summary.html
+== dynamic-add-paragraph-before-summary.html open-single-summary.html
+== dynamic-add-paragraph-before-summary-close.html single-summary.html
+== dynamic-add-paragraph-after-summary.html open-single-summary.html
+== dynamic-add-paragraph-after-summary-close.html single-summary.html
+== dynamic-add-details.html open-single-summary.html
+== dynamic-add-first-summary.html open-multiple-summary.html
+== dynamic-add-second-summary.html open-multiple-summary.html
 
 # Remove elements dynamically
-pref(dom.details_element.enabled,true) == dynamic-remove-single-summary.html open-no-summary.html
-pref(dom.details_element.enabled,true) == dynamic-remove-summary-not-first-child.html open-no-summary.html
-pref(dom.details_element.enabled,true) == dynamic-remove-first-summary.html open-single-summary.html
-pref(dom.details_element.enabled,true) == dynamic-remove-second-summary.html open-single-summary.html
+== dynamic-remove-single-summary.html open-no-summary.html
+== dynamic-remove-summary-not-first-child.html open-no-summary.html
+== dynamic-remove-first-summary.html open-single-summary.html
+== dynamic-remove-second-summary.html open-single-summary.html
 
 # Toggle details by open attribute
-pref(dom.details_element.enabled,true) == close-nested-details.html close-nested-details-ref.html
-pref(dom.details_element.enabled,true) == open-nested-details.html open-nested-details-ref.html
+== close-nested-details.html close-nested-details-ref.html
+== open-nested-details.html open-nested-details-ref.html
 
 # With 'overflow' property
-pref(dom.details_element.enabled,true) == overflow-hidden-open-details.html overflow-hidden-open-details-ref.html
-pref(dom.details_element.enabled,true) == overflow-auto-open-details.html overflow-auto-open-details-ref.html
+== overflow-hidden-open-details.html overflow-hidden-open-details-ref.html
+== overflow-auto-open-details.html overflow-auto-open-details-ref.html
 
 # With pagination property
-pref(dom.details_element.enabled,true) == details-page-break-after-1.html details-two-pages.html
-pref(dom.details_element.enabled,true) == details-page-break-after-2.html details-two-pages.html
-pref(dom.details_element.enabled,true) == details-page-break-before-1.html details-two-pages.html
-pref(dom.details_element.enabled,true) == details-page-break-before-2.html details-two-pages.html
+== details-page-break-after-1.html details-two-pages.html
+== details-page-break-after-2.html details-two-pages.html
+== details-page-break-before-1.html details-two-pages.html
+== details-page-break-before-2.html details-two-pages.html
 
 # Various properties on details or summary
-pref(dom.details_element.enabled,true) == details-display-inline.html details-display-inline-ref.html
-pref(dom.details_element.enabled,true) == details-percentage-height-children.html details-percentage-height-children-ref.html
-pref(dom.details_element.enabled,true) == details-absolute-children.html details-absolute-children-ref.html
-pref(dom.details_element.enabled,true) == details-three-columns.html details-three-columns-ref.html
-pref(dom.details_element.enabled,true) == details-writing-mode.html details-writing-mode-ref.html
-pref(dom.details_element.enabled,true) == details-in-ol.html details-in-ol-ref.html
+== details-display-inline.html details-display-inline-ref.html
+== details-percentage-height-children.html details-percentage-height-children-ref.html
+== details-absolute-children.html details-absolute-children-ref.html
+== details-three-columns.html details-three-columns-ref.html
+== details-writing-mode.html details-writing-mode-ref.html
+== details-in-ol.html details-in-ol-ref.html
 
 # Dispatch mouse click to summary
-pref(dom.details_element.enabled,true) == mouse-click-single-summary.html open-single-summary.html
-pref(dom.details_element.enabled,true) == mouse-click-twice-single-summary.html single-summary.html
-pref(dom.details_element.enabled,true) == mouse-click-open-single-summary.html single-summary.html
-pref(dom.details_element.enabled,true) == mouse-click-twice-open-single-summary.html open-single-summary.html
-pref(dom.details_element.enabled,true) == mouse-click-open-second-summary.html open-multiple-summary.html
-pref(dom.details_element.enabled,true) == mouse-click-overflow-hidden-details.html overflow-hidden-open-details.html
-pref(dom.details_element.enabled,true) == mouse-click-twice-overflow-hidden-details.html overflow-hidden-details.html
-pref(dom.details_element.enabled,true) == mouse-click-overflow-auto-details.html overflow-auto-open-details.html
-pref(dom.details_element.enabled,true) == mouse-click-twice-overflow-auto-details.html overflow-auto-details.html
-pref(dom.details_element.enabled,true) == mouse-click-display-none-details.html open-single-summary.html
-pref(dom.details_element.enabled,true) == mouse-click-change-details-to-display-none.html open-single-summary.html
-pref(dom.details_element.enabled,true) == mouse-click-change-summary-to-display-none.html mouse-click-change-summary-to-display-none-ref.html
-pref(dom.details_element.enabled,true) == mouse-click-move-summary-to-different-details.html mouse-click-move-summary-to-different-details-ref.html
+== mouse-click-single-summary.html open-single-summary.html
+== mouse-click-twice-single-summary.html single-summary.html
+== mouse-click-open-single-summary.html single-summary.html
+== mouse-click-twice-open-single-summary.html open-single-summary.html
+== mouse-click-open-second-summary.html open-multiple-summary.html
+== mouse-click-overflow-hidden-details.html overflow-hidden-open-details.html
+== mouse-click-twice-overflow-hidden-details.html overflow-hidden-details.html
+== mouse-click-overflow-auto-details.html overflow-auto-open-details.html
+== mouse-click-twice-overflow-auto-details.html overflow-auto-details.html
+== mouse-click-display-none-details.html open-single-summary.html
+== mouse-click-change-details-to-display-none.html open-single-summary.html
+== mouse-click-change-summary-to-display-none.html mouse-click-change-summary-to-display-none-ref.html
+== mouse-click-move-summary-to-different-details.html mouse-click-move-summary-to-different-details-ref.html
 
 # Dispatch mouse click to out-of-flow details or summary
-pref(dom.details_element.enabled,true) == mouse-click-fixed-summary.html open-fixed-summary.html
-pref(dom.details_element.enabled,true) == mouse-click-twice-fixed-summary.html fixed-summary.html
-pref(dom.details_element.enabled,true) == mouse-click-float-details.html open-float-details.html
-pref(dom.details_element.enabled,true) == mouse-click-twice-float-details.html float-details.html
+== mouse-click-fixed-summary.html open-fixed-summary.html
+== mouse-click-twice-fixed-summary.html fixed-summary.html
+== mouse-click-float-details.html open-float-details.html
+== mouse-click-twice-float-details.html float-details.html
 
 # Dispatch keyboard event to summary
-pref(dom.details_element.enabled,true) == key-enter-single-summary.html open-single-summary.html
-pref(dom.details_element.enabled,true) == key-enter-open-second-summary.html open-multiple-summary.html
-pref(dom.details_element.enabled,true) == key-enter-prevent-default.html single-summary.html
-pref(dom.details_element.enabled,true) == key-space-single-summary.html open-single-summary.html
+== key-enter-single-summary.html open-single-summary.html
+== key-enter-open-second-summary.html open-multiple-summary.html
+== key-enter-prevent-default.html single-summary.html
+== key-space-single-summary.html open-single-summary.html