update

src/sass/gnome-shell/common/_popovers.scss

@@ -186,25 +186,6 @@ $popop_menuitem_radius: $wm_radius - 4px;
   &:rtl { text-align: left; }
 }
 
-// separator
-.popup-separator-menu-item {
-  background: none;
-  border: none;
-  padding-top: 0 !important;
-  padding-bottom: 0 !important;
-
-  .popup-separator-menu-item-separator {
-    height: 1px; //not really the whole box
-    margin: 0;
-    background-color: $borders_color;
-
-    .popup-sub-menu & { //submenu separators
-      margin: 0 32px 0 0;
-      height: 1px;
-    }
-  }
-}
-
 // desktop background menu
 .background-menu {
   -boxpointer-gap: $base_margin;

src/sass/gnome-shell/common/_scrollbars.scss

@@ -1,8 +1,8 @@
 /* Scrollbars */
 
 StScrollView {
-  &.vfade { -st-vfade-offset: 32px; }
+  &.vfade { -st-vfade-offset: 68px; }
-  &.hfade { -st-hfade-offset: 32px; }
+  &.hfade { -st-hfade-offset: 68px; }
 }
 
 StScrollBar {

src/sass/gnome-shell/widgets-3-28/_popovers.scss

@@ -4,6 +4,25 @@
   &:rtl { padding-right: 0; padding-left: 1.5em; }
 }
 
+// separator
+.popup-separator-menu-item {
+  background: none;
+  border: none;
+  padding-top: 0 !important;
+  padding-bottom: 0 !important;
+
+  .popup-separator-menu-item-separator {
+    height: 1px; //not really the whole box
+    margin: 0;
+    background-color: $borders_color;
+
+    .popup-sub-menu & { //submenu separators
+      margin: 0 32px 0 0;
+      height: 1px;
+    }
+  }
+}
+
 // system status popover menu
 .aggregate-menu {
   .popup-sub-menu .popup-menu-item > :first-child {

src/sass/gnome-shell/widgets-40-0/_popovers.scss

@@ -4,6 +4,25 @@
   &:rtl { padding-right: 0; padding-left: 1.5em; }
 }
 
+// separator
+.popup-separator-menu-item {
+  background: none;
+  border: none;
+  padding-top: 0 !important;
+  padding-bottom: 0 !important;
+
+  .popup-separator-menu-item-separator {
+    height: 1px; //not really the whole box
+    margin: 0;
+    background-color: $borders_color;
+
+    .popup-sub-menu & { //submenu separators
+      margin: 0 32px 0 0;
+      height: 1px;
+    }
+  }
+}
+
 // system status popover menu
 .aggregate-menu {
   .popup-sub-menu .popup-menu-item > :first-child {

src/sass/gnome-shell/widgets-42-0/_popovers.scss

@@ -6,7 +6,32 @@
 
 // separator
 .popup-separator-menu-item {
-  margin: 6px 32px;
+  border: none !important;
+
+  &:ltr { margin-right: $base_padding; }
+  &:rtl { margin-left: $base_padding; }
+
+  .popup-separator-menu-item-separator {
+    height: 1px; //not really the whole box
+    background-color: $borders_color;
+  }
+
+  .popup-menu-ornament {
+    width: 0 !important;
+  }
+
+  // separators in submenus
+  .popup-sub-menu & {
+    background-color: transparent;
+
+    // account for ornament
+    &:ltr { margin-right: 2.5em; }
+    &:rtl { margin-left: 2.5em; }
+
+    .popup-separator-menu-item-separator {
+      background-color: $borders_color;
+    }
+  }
 }
 
 // system status popover menu