update

src/sass/gtk/_common-3.0.scss

@@ -1052,6 +1052,11 @@ toolbar {
   border-width: 0 1px 1px;
   border-color: $divider;
   background-color: $base-alt;
+
+  .frame & {
+    border-width: 1px 0 0;
+    background-color: transparent;
+  }
 }
 
 searchbar > revealer > box,
@@ -1905,7 +1910,12 @@ notebook {
     border-radius: $modal-radius + $space-size;
   }
 
-  &.frame frame {
+  &.frame {
+    scrolledwindow.frame {
+      border: none;
+    }
+
+    frame {
       > border {
         border: none;
         border-radius: $modal-radius;
@@ -1917,6 +1927,7 @@ notebook {
         row.activatable { border-radius: $corner-radius; }
       }
     }
+  }
 
   > header {
     border: none;
@@ -2407,7 +2418,7 @@ treeview.view {
     padding: 0;
     margin: 0;
 
-    &:not(:hover):not(:disabled):not(:checked):not(:indeterminate) {
+    &:not(:disabled):not(:checked):not(:indeterminate) {
       background-color: $divider;
     }
 
@@ -2416,7 +2427,7 @@ treeview.view {
     }
   }
 
-  &:selected, &:selected:focus {
+  &, &:hover, &:selected {
     radio, check {
       &:checked, &:indeterminate {
         background-color: $assets-color;