diff --git a/chrome/multi-row_tabs.css b/chrome/multi-row_tabs.css
index 4921210..76e184a 100644
--- a/chrome/multi-row_tabs.css
+++ b/chrome/multi-row_tabs.css
@@ -73,6 +73,9 @@ See the above repository for updates as well as full license text. */
 
 .tabbrowser-tab > stack{ width: 100%; height: 100% }
 
+/* remove bottom margin so it doesn't throw off row height computation */
+#tabs-newtab-button{ margin-bottom: 0 !important; }
+
 #alltabs-button,
 :root:not([customizing]) #TabsToolbar #new-tab-button,
 #tabbrowser-arrowscrollbox > spacer,
diff --git a/chrome/multi-row_tabs_below_content.css b/chrome/multi-row_tabs_below_content.css
index 6351a10..3315794 100644
--- a/chrome/multi-row_tabs_below_content.css
+++ b/chrome/multi-row_tabs_below_content.css
@@ -183,6 +183,9 @@ See the above repository for updates as well as full license text. */
   /* This should fix potential flash that could occur when bottom border is hovered to show tabs in fullscreen mode */
   #tabbrowser-tabpanels{ background-color: var(--lwt-accent-color) !important; }
 
+  /* remove bottom margin so it doesn't throw off row height computation */
+  #tabs-newtab-button{ margin-bottom: 0 !important; }
+
   /* Hide some things that are unnecessary in multi-row below content mode */
 
   #TabsToolbar > #window-controls,