New marker div

display/display.css

@@ -281,7 +281,10 @@
     background-color: #ffffff;
     color: #444;
     cursor: pointer;
-    padding: 9px;
+    padding-top: 9px;
+    padding-bottom: 9px;
+    padding-right: 9px;
+    padding-left: 0px;
     width: 100%;
     border: 2px solid white;
     text-align: left;
@@ -289,6 +292,7 @@
     font-size: 15px;
     display: flex;
     flex-direction: column;
+    position: relative;
 }
 
 .activation-hover, .collapsible:hover {
@@ -321,3 +325,12 @@
 .activation-hover, .link-neighbor:hover {
     background-color: #ccc;
 }
+
+.marker-div {
+    position: absolute;
+    width: 100%;
+    height: 2px;
+    border: 1px solid red;
+    bottom: 0;
+    left: 0;
+}

display/overlays/neighbors.js

@@ -69,11 +69,16 @@ class NodeNeighborOverlay {
             );
             collTab.className = "collapsible";
             collTab.innerText = cls;
-            collTab.style.borderLeftColor = color;
-            collTab.style.borderLeftWidth = "8px";
             collTab.type = cls;
             this.tabNavHandles[cls] = collTab;
 
+            const collTabMarker = Helpers.createDiv(
+                "marker-div",
+                collTab
+            );
+            collTabMarker.style.borderColor = color;
+            collTabMarker.style.backgroundColor = color;
+
             // Content of the different tabs
             const collTabContent = Helpers.createDiv(
                 "neighbor-content-links",