diff --git a/common/gtk-3.0/3.20/gtk-dark.css b/common/gtk-3.0/3.20/gtk-dark.css
index 7ebd155..62b05ec 100644
--- a/common/gtk-3.0/3.20/gtk-dark.css
+++ b/common/gtk-3.0/3.20/gtk-dark.css
@@ -1628,6 +1628,12 @@ notebook {
     border: 1px solid #2b2e39; }
     notebook.frame > header {
       margin: -1px; }
+      notebook.frame > header.top, notebook.frame > header.bottom {
+        padding-left: 0;
+        padding-right: 0; }
+      notebook.frame > header.left, notebook.frame > header.right {
+        padding-top: 0;
+        padding-bottom: 0; }
   notebook > stack:not(:only-child) {
     background-color: #404552; }
   notebook > header {
@@ -1650,8 +1656,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-bottom: none;
-        margin-right: -1px;
         border-radius: 1px 1px 0 0; }
+        notebook > header.top > tabs > tab + tab {
+          margin-left: -1px; }
     notebook > header.bottom {
       padding-top: 0; }
       notebook > header.bottom > tabs > tab {
@@ -1661,8 +1668,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-top: none;
-        margin-right: -1px;
         border-radius: 0 0 1px 1px; }
+        notebook > header.bottom > tabs > tab + tab {
+          margin-left: -1px; }
     notebook > header.right {
       padding-left: 0; }
       notebook > header.right > tabs > tab {
@@ -1672,8 +1680,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-left: none;
-        margin-bottom: -1px;
         border-radius: 0 1px 1px 0; }
+        notebook > header.right > tabs > tab + tab {
+          margin-top: -1px; }
     notebook > header.left {
       padding-right: 0; }
       notebook > header.left > tabs > tab {
@@ -1683,8 +1692,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-right: none;
-        margin-bottom: -1px;
         border-radius: 1px 0 0 1px; }
+        notebook > header.left > tabs > tab + tab {
+          margin-top: -1px; }
     notebook > header.top > tabs > arrow.up, notebook > header.bottom > tabs > arrow.up {
       -gtk-icon-source: -gtk-icontheme("pan-end-symbolic"); }
       notebook > header.top > tabs > arrow.up:last-child, notebook > header.bottom > tabs > arrow.up:last-child {
@@ -1709,14 +1719,21 @@ notebook {
         color: #D3DAE3; }
       notebook > header > tabs > arrow:disabled {
         color: rgba(211, 218, 227, 0.15); }
+    notebook > header.top > tabs > tab:hover:not(:checked) {
+      box-shadow: inset 0 -1px #2b2e39; }
+    notebook > header.bottom > tabs > tab:hover:not(:checked) {
+      box-shadow: inset 0 1px #2b2e39; }
+    notebook > header.left > tabs > tab:hover:not(:checked) {
+      box-shadow: inset -1px 0 #2b2e39; }
+    notebook > header.right > tabs > tab:hover:not(:checked) {
+      box-shadow: inset 1px 0 #2b2e39; }
     notebook > header > tabs > tab {
       color: rgba(211, 218, 227, 0.45);
       background-color: rgba(64, 69, 82, 0); }
       notebook > header > tabs > tab:hover:not(:checked) {
         color: rgba(211, 218, 227, 0.725);
         background-color: rgba(64, 69, 82, 0.5);
-        border-color: #2b2e39;
-        box-shadow: inset 0 -1px #2b2e39; }
+        border-color: #2b2e39; }
       notebook > header > tabs > tab:checked {
         color: #D3DAE3;
         background-color: #404552;
diff --git a/common/gtk-3.0/3.20/gtk-darker.css b/common/gtk-3.0/3.20/gtk-darker.css
index f702e8f..0f74ebf 100644
--- a/common/gtk-3.0/3.20/gtk-darker.css
+++ b/common/gtk-3.0/3.20/gtk-darker.css
@@ -1627,6 +1627,12 @@ notebook {
     border: 1px solid #dcdfe3; }
     notebook.frame > header {
       margin: -1px; }
+      notebook.frame > header.top, notebook.frame > header.bottom {
+        padding-left: 0;
+        padding-right: 0; }
+      notebook.frame > header.left, notebook.frame > header.right {
+        padding-top: 0;
+        padding-bottom: 0; }
   notebook > stack:not(:only-child) {
     background-color: #ffffff; }
   notebook > header {
@@ -1649,8 +1655,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-bottom: none;
-        margin-right: -1px;
         border-radius: 1px 1px 0 0; }
+        notebook > header.top > tabs > tab + tab {
+          margin-left: -1px; }
     notebook > header.bottom {
       padding-top: 0; }
       notebook > header.bottom > tabs > tab {
@@ -1660,8 +1667,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-top: none;
-        margin-right: -1px;
         border-radius: 0 0 1px 1px; }
+        notebook > header.bottom > tabs > tab + tab {
+          margin-left: -1px; }
     notebook > header.right {
       padding-left: 0; }
       notebook > header.right > tabs > tab {
@@ -1671,8 +1679,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-left: none;
-        margin-bottom: -1px;
         border-radius: 0 1px 1px 0; }
+        notebook > header.right > tabs > tab + tab {
+          margin-top: -1px; }
     notebook > header.left {
       padding-right: 0; }
       notebook > header.left > tabs > tab {
@@ -1682,8 +1691,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-right: none;
-        margin-bottom: -1px;
         border-radius: 1px 0 0 1px; }
+        notebook > header.left > tabs > tab + tab {
+          margin-top: -1px; }
     notebook > header.top > tabs > arrow.up, notebook > header.bottom > tabs > arrow.up {
       -gtk-icon-source: -gtk-icontheme("pan-end-symbolic"); }
       notebook > header.top > tabs > arrow.up:last-child, notebook > header.bottom > tabs > arrow.up:last-child {
@@ -1708,14 +1718,21 @@ notebook {
         color: #5c616c; }
       notebook > header > tabs > arrow:disabled {
         color: rgba(92, 97, 108, 0.25); }
+    notebook > header.top > tabs > tab:hover:not(:checked) {
+      box-shadow: inset 0 -1px #dcdfe3; }
+    notebook > header.bottom > tabs > tab:hover:not(:checked) {
+      box-shadow: inset 0 1px #dcdfe3; }
+    notebook > header.left > tabs > tab:hover:not(:checked) {
+      box-shadow: inset -1px 0 #dcdfe3; }
+    notebook > header.right > tabs > tab:hover:not(:checked) {
+      box-shadow: inset 1px 0 #dcdfe3; }
     notebook > header > tabs > tab {
       color: rgba(92, 97, 108, 0.55);
       background-color: rgba(255, 255, 255, 0); }
       notebook > header > tabs > tab:hover:not(:checked) {
         color: rgba(92, 97, 108, 0.775);
         background-color: rgba(255, 255, 255, 0.5);
-        border-color: #dcdfe3;
-        box-shadow: inset 0 -1px #dcdfe3; }
+        border-color: #dcdfe3; }
       notebook > header > tabs > tab:checked {
         color: #5c616c;
         background-color: #ffffff;
diff --git a/common/gtk-3.0/3.20/gtk-solid-dark.css b/common/gtk-3.0/3.20/gtk-solid-dark.css
index aa7d699..e09c664 100644
--- a/common/gtk-3.0/3.20/gtk-solid-dark.css
+++ b/common/gtk-3.0/3.20/gtk-solid-dark.css
@@ -1628,6 +1628,12 @@ notebook {
     border: 1px solid #2b2e39; }
     notebook.frame > header {
       margin: -1px; }
+      notebook.frame > header.top, notebook.frame > header.bottom {
+        padding-left: 0;
+        padding-right: 0; }
+      notebook.frame > header.left, notebook.frame > header.right {
+        padding-top: 0;
+        padding-bottom: 0; }
   notebook > stack:not(:only-child) {
     background-color: #404552; }
   notebook > header {
@@ -1650,8 +1656,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-bottom: none;
-        margin-right: -1px;
         border-radius: 1px 1px 0 0; }
+        notebook > header.top > tabs > tab + tab {
+          margin-left: -1px; }
     notebook > header.bottom {
       padding-top: 0; }
       notebook > header.bottom > tabs > tab {
@@ -1661,8 +1668,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-top: none;
-        margin-right: -1px;
         border-radius: 0 0 1px 1px; }
+        notebook > header.bottom > tabs > tab + tab {
+          margin-left: -1px; }
     notebook > header.right {
       padding-left: 0; }
       notebook > header.right > tabs > tab {
@@ -1672,8 +1680,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-left: none;
-        margin-bottom: -1px;
         border-radius: 0 1px 1px 0; }
+        notebook > header.right > tabs > tab + tab {
+          margin-top: -1px; }
     notebook > header.left {
       padding-right: 0; }
       notebook > header.left > tabs > tab {
@@ -1683,8 +1692,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-right: none;
-        margin-bottom: -1px;
         border-radius: 1px 0 0 1px; }
+        notebook > header.left > tabs > tab + tab {
+          margin-top: -1px; }
     notebook > header.top > tabs > arrow.up, notebook > header.bottom > tabs > arrow.up {
       -gtk-icon-source: -gtk-icontheme("pan-end-symbolic"); }
       notebook > header.top > tabs > arrow.up:last-child, notebook > header.bottom > tabs > arrow.up:last-child {
@@ -1709,14 +1719,21 @@ notebook {
         color: #D3DAE3; }
       notebook > header > tabs > arrow:disabled {
         color: rgba(211, 218, 227, 0.15); }
+    notebook > header.top > tabs > tab:hover:not(:checked) {
+      box-shadow: inset 0 -1px #2b2e39; }
+    notebook > header.bottom > tabs > tab:hover:not(:checked) {
+      box-shadow: inset 0 1px #2b2e39; }
+    notebook > header.left > tabs > tab:hover:not(:checked) {
+      box-shadow: inset -1px 0 #2b2e39; }
+    notebook > header.right > tabs > tab:hover:not(:checked) {
+      box-shadow: inset 1px 0 #2b2e39; }
     notebook > header > tabs > tab {
       color: rgba(211, 218, 227, 0.45);
       background-color: rgba(64, 69, 82, 0); }
       notebook > header > tabs > tab:hover:not(:checked) {
         color: rgba(211, 218, 227, 0.725);
         background-color: rgba(64, 69, 82, 0.5);
-        border-color: #2b2e39;
-        box-shadow: inset 0 -1px #2b2e39; }
+        border-color: #2b2e39; }
       notebook > header > tabs > tab:checked {
         color: #D3DAE3;
         background-color: #404552;
diff --git a/common/gtk-3.0/3.20/gtk-solid-darker.css b/common/gtk-3.0/3.20/gtk-solid-darker.css
index 677bc68..2bb5a22 100644
--- a/common/gtk-3.0/3.20/gtk-solid-darker.css
+++ b/common/gtk-3.0/3.20/gtk-solid-darker.css
@@ -1627,6 +1627,12 @@ notebook {
     border: 1px solid #dcdfe3; }
     notebook.frame > header {
       margin: -1px; }
+      notebook.frame > header.top, notebook.frame > header.bottom {
+        padding-left: 0;
+        padding-right: 0; }
+      notebook.frame > header.left, notebook.frame > header.right {
+        padding-top: 0;
+        padding-bottom: 0; }
   notebook > stack:not(:only-child) {
     background-color: #ffffff; }
   notebook > header {
@@ -1649,8 +1655,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-bottom: none;
-        margin-right: -1px;
         border-radius: 1px 1px 0 0; }
+        notebook > header.top > tabs > tab + tab {
+          margin-left: -1px; }
     notebook > header.bottom {
       padding-top: 0; }
       notebook > header.bottom > tabs > tab {
@@ -1660,8 +1667,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-top: none;
-        margin-right: -1px;
         border-radius: 0 0 1px 1px; }
+        notebook > header.bottom > tabs > tab + tab {
+          margin-left: -1px; }
     notebook > header.right {
       padding-left: 0; }
       notebook > header.right > tabs > tab {
@@ -1671,8 +1679,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-left: none;
-        margin-bottom: -1px;
         border-radius: 0 1px 1px 0; }
+        notebook > header.right > tabs > tab + tab {
+          margin-top: -1px; }
     notebook > header.left {
       padding-right: 0; }
       notebook > header.left > tabs > tab {
@@ -1682,8 +1691,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-right: none;
-        margin-bottom: -1px;
         border-radius: 1px 0 0 1px; }
+        notebook > header.left > tabs > tab + tab {
+          margin-top: -1px; }
     notebook > header.top > tabs > arrow.up, notebook > header.bottom > tabs > arrow.up {
       -gtk-icon-source: -gtk-icontheme("pan-end-symbolic"); }
       notebook > header.top > tabs > arrow.up:last-child, notebook > header.bottom > tabs > arrow.up:last-child {
@@ -1708,14 +1718,21 @@ notebook {
         color: #5c616c; }
       notebook > header > tabs > arrow:disabled {
         color: rgba(92, 97, 108, 0.25); }
+    notebook > header.top > tabs > tab:hover:not(:checked) {
+      box-shadow: inset 0 -1px #dcdfe3; }
+    notebook > header.bottom > tabs > tab:hover:not(:checked) {
+      box-shadow: inset 0 1px #dcdfe3; }
+    notebook > header.left > tabs > tab:hover:not(:checked) {
+      box-shadow: inset -1px 0 #dcdfe3; }
+    notebook > header.right > tabs > tab:hover:not(:checked) {
+      box-shadow: inset 1px 0 #dcdfe3; }
     notebook > header > tabs > tab {
       color: rgba(92, 97, 108, 0.55);
       background-color: rgba(255, 255, 255, 0); }
       notebook > header > tabs > tab:hover:not(:checked) {
         color: rgba(92, 97, 108, 0.775);
         background-color: rgba(255, 255, 255, 0.5);
-        border-color: #dcdfe3;
-        box-shadow: inset 0 -1px #dcdfe3; }
+        border-color: #dcdfe3; }
       notebook > header > tabs > tab:checked {
         color: #5c616c;
         background-color: #ffffff;
diff --git a/common/gtk-3.0/3.20/gtk-solid.css b/common/gtk-3.0/3.20/gtk-solid.css
index eec4be8..a511a00 100644
--- a/common/gtk-3.0/3.20/gtk-solid.css
+++ b/common/gtk-3.0/3.20/gtk-solid.css
@@ -1631,6 +1631,12 @@ notebook {
     border: 1px solid #dcdfe3; }
     notebook.frame > header {
       margin: -1px; }
+      notebook.frame > header.top, notebook.frame > header.bottom {
+        padding-left: 0;
+        padding-right: 0; }
+      notebook.frame > header.left, notebook.frame > header.right {
+        padding-top: 0;
+        padding-bottom: 0; }
   notebook > stack:not(:only-child) {
     background-color: #ffffff; }
   notebook > header {
@@ -1653,8 +1659,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-bottom: none;
-        margin-right: -1px;
         border-radius: 1px 1px 0 0; }
+        notebook > header.top > tabs > tab + tab {
+          margin-left: -1px; }
     notebook > header.bottom {
       padding-top: 0; }
       notebook > header.bottom > tabs > tab {
@@ -1664,8 +1671,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-top: none;
-        margin-right: -1px;
         border-radius: 0 0 1px 1px; }
+        notebook > header.bottom > tabs > tab + tab {
+          margin-left: -1px; }
     notebook > header.right {
       padding-left: 0; }
       notebook > header.right > tabs > tab {
@@ -1675,8 +1683,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-left: none;
-        margin-bottom: -1px;
         border-radius: 0 1px 1px 0; }
+        notebook > header.right > tabs > tab + tab {
+          margin-top: -1px; }
     notebook > header.left {
       padding-right: 0; }
       notebook > header.left > tabs > tab {
@@ -1686,8 +1695,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-right: none;
-        margin-bottom: -1px;
         border-radius: 1px 0 0 1px; }
+        notebook > header.left > tabs > tab + tab {
+          margin-top: -1px; }
     notebook > header.top > tabs > arrow.up, notebook > header.bottom > tabs > arrow.up {
       -gtk-icon-source: -gtk-icontheme("pan-end-symbolic"); }
       notebook > header.top > tabs > arrow.up:last-child, notebook > header.bottom > tabs > arrow.up:last-child {
@@ -1712,14 +1722,21 @@ notebook {
         color: #5c616c; }
       notebook > header > tabs > arrow:disabled {
         color: rgba(92, 97, 108, 0.25); }
+    notebook > header.top > tabs > tab:hover:not(:checked) {
+      box-shadow: inset 0 -1px #dcdfe3; }
+    notebook > header.bottom > tabs > tab:hover:not(:checked) {
+      box-shadow: inset 0 1px #dcdfe3; }
+    notebook > header.left > tabs > tab:hover:not(:checked) {
+      box-shadow: inset -1px 0 #dcdfe3; }
+    notebook > header.right > tabs > tab:hover:not(:checked) {
+      box-shadow: inset 1px 0 #dcdfe3; }
     notebook > header > tabs > tab {
       color: rgba(92, 97, 108, 0.55);
       background-color: rgba(255, 255, 255, 0); }
       notebook > header > tabs > tab:hover:not(:checked) {
         color: rgba(92, 97, 108, 0.775);
         background-color: rgba(255, 255, 255, 0.5);
-        border-color: #dcdfe3;
-        box-shadow: inset 0 -1px #dcdfe3; }
+        border-color: #dcdfe3; }
       notebook > header > tabs > tab:checked {
         color: #5c616c;
         background-color: #ffffff;
diff --git a/common/gtk-3.0/3.20/gtk.css b/common/gtk-3.0/3.20/gtk.css
index 03e7425..6999c14 100644
--- a/common/gtk-3.0/3.20/gtk.css
+++ b/common/gtk-3.0/3.20/gtk.css
@@ -1631,6 +1631,12 @@ notebook {
     border: 1px solid #dcdfe3; }
     notebook.frame > header {
       margin: -1px; }
+      notebook.frame > header.top, notebook.frame > header.bottom {
+        padding-left: 0;
+        padding-right: 0; }
+      notebook.frame > header.left, notebook.frame > header.right {
+        padding-top: 0;
+        padding-bottom: 0; }
   notebook > stack:not(:only-child) {
     background-color: #ffffff; }
   notebook > header {
@@ -1653,8 +1659,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-bottom: none;
-        margin-right: -1px;
         border-radius: 1px 1px 0 0; }
+        notebook > header.top > tabs > tab + tab {
+          margin-left: -1px; }
     notebook > header.bottom {
       padding-top: 0; }
       notebook > header.bottom > tabs > tab {
@@ -1664,8 +1671,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-top: none;
-        margin-right: -1px;
         border-radius: 0 0 1px 1px; }
+        notebook > header.bottom > tabs > tab + tab {
+          margin-left: -1px; }
     notebook > header.right {
       padding-left: 0; }
       notebook > header.right > tabs > tab {
@@ -1675,8 +1683,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-left: none;
-        margin-bottom: -1px;
         border-radius: 0 1px 1px 0; }
+        notebook > header.right > tabs > tab + tab {
+          margin-top: -1px; }
     notebook > header.left {
       padding-right: 0; }
       notebook > header.left > tabs > tab {
@@ -1686,8 +1695,9 @@ notebook {
         outline-offset: -4px;
         border: 1px solid transparent;
         border-right: none;
-        margin-bottom: -1px;
         border-radius: 1px 0 0 1px; }
+        notebook > header.left > tabs > tab + tab {
+          margin-top: -1px; }
     notebook > header.top > tabs > arrow.up, notebook > header.bottom > tabs > arrow.up {
       -gtk-icon-source: -gtk-icontheme("pan-end-symbolic"); }
       notebook > header.top > tabs > arrow.up:last-child, notebook > header.bottom > tabs > arrow.up:last-child {
@@ -1712,14 +1722,21 @@ notebook {
         color: #5c616c; }
       notebook > header > tabs > arrow:disabled {
         color: rgba(92, 97, 108, 0.25); }
+    notebook > header.top > tabs > tab:hover:not(:checked) {
+      box-shadow: inset 0 -1px #dcdfe3; }
+    notebook > header.bottom > tabs > tab:hover:not(:checked) {
+      box-shadow: inset 0 1px #dcdfe3; }
+    notebook > header.left > tabs > tab:hover:not(:checked) {
+      box-shadow: inset -1px 0 #dcdfe3; }
+    notebook > header.right > tabs > tab:hover:not(:checked) {
+      box-shadow: inset 1px 0 #dcdfe3; }
     notebook > header > tabs > tab {
       color: rgba(92, 97, 108, 0.55);
       background-color: rgba(255, 255, 255, 0); }
       notebook > header > tabs > tab:hover:not(:checked) {
         color: rgba(92, 97, 108, 0.775);
         background-color: rgba(255, 255, 255, 0.5);
-        border-color: #dcdfe3;
-        box-shadow: inset 0 -1px #dcdfe3; }
+        border-color: #dcdfe3; }
       notebook > header > tabs > tab:checked {
         color: #5c616c;
         background-color: #ffffff;
diff --git a/common/gtk-3.0/3.20/sass/_common.scss b/common/gtk-3.0/3.20/sass/_common.scss
index 2c8d750..aa0286b 100644
--- a/common/gtk-3.0/3.20/sass/_common.scss
+++ b/common/gtk-3.0/3.20/sass/_common.scss
@@ -1725,7 +1725,12 @@ notebook {
   &.frame {
     border: 1px solid $borders_color;
 
-    > header { margin: -1px; }  // ugly hack to hide the borders around the header
+    > header {
+      margin: -1px;  // ugly hack to hide the borders around the header
+
+      &.top, &.bottom { padding-left: 0; padding-right: 0; }
+      &.left, &.right { padding-top: 0; padding-bottom: 0; }
+    }
   }
 
   > stack:not(:only-child) { // the :not(:only-child) is for "hidden" notebooks
@@ -1757,8 +1762,10 @@ notebook {
           border-#{$_bpos}: none;
 
           // tab overlap
-          @if $_pos==top or $_pos==bottom { margin-right: -1px; }
-          @else { margin-bottom: -1px; }
+          + tab {
+            @if $_pos==top or $_pos==bottom { margin-left: -1px; }
+            @else { margin-top: -1px; }
+          }
 
           // tab border radius
           @if $_pos==top { border-radius: 1px 1px 0 0; }
@@ -1796,7 +1803,14 @@ notebook {
       &:active { color: $fg_color; }
       &:disabled { color: transparentize($insensitive_fg_color,0.3); }
     }
+
     // tab colors
+
+    &.top > tabs > tab:hover:not(:checked) { box-shadow: inset 0 -1px $borders_color; }
+    &.bottom > tabs > tab:hover:not(:checked) { box-shadow: inset 0 1px $borders_color; }
+    &.left > tabs > tab:hover:not(:checked) { box-shadow: inset -1px 0 $borders_color; }
+    &.right > tabs > tab:hover:not(:checked) { box-shadow: inset 1px 0 $borders_color; }
+
     > tabs > tab {
       color: $insensitive_fg_color;
       background-color: transparentize($base_color, 1);
@@ -1805,7 +1819,6 @@ notebook {
         color: mix($fg_color, $insensitive_fg_color, 50%);
         background-color: transparentize($base_color, 0.5);
         border-color: $borders_color;
-        box-shadow: inset 0 -1px $borders_color;
       }
       &:checked {
         color: $fg_color;