diff --git a/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight.js b/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight.js
index 229ae43..665e4a6 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight.js
@@ -119,6 +119,30 @@
     return null;
   }
 
+  _toggleRangeElHighlight(threadEl, highlightRange = false) {
+    // We don't want to re-create the line just for highlighting the range which
+    // is creating annoying bugs: @see Issue 12934
+    // As gr-ranged-comment-layer now does not notify the layer re-render and
+    // lack of access to the thread or the lineEl from the ranged-comment-layer,
+    // need to update range class for styles here.
+    const currentLine = threadEl.assignedSlot.parentElement.previousSibling;
+    if (currentLine && currentLine.querySelector) {
+      if (highlightRange) {
+        const rangeNode = currentLine.querySelector('.range');
+        if (rangeNode) {
+          rangeNode.classList.add('rangeHighlight');
+          rangeNode.classList.remove('range');
+        }
+      } else {
+        const rangeNode = currentLine.querySelector('.rangeHighlight');
+        if (rangeNode) {
+          rangeNode.classList.remove('rangeHighlight');
+          rangeNode.classList.add('range');
+        }
+      }
+    }
+  }
+
   _handleCommentThreadMouseenter(e) {
     const threadEl = this._getThreadEl(e);
     const index = this._indexForThreadEl(threadEl);
@@ -126,6 +150,8 @@
     if (index !== undefined) {
       this.set(['commentRanges', index, 'hovering'], true);
     }
+
+    this._toggleRangeElHighlight(threadEl, /* highlightRange= */ true);
   }
 
   _handleCommentThreadMouseleave(e) {
@@ -135,6 +161,8 @@
     if (index !== undefined) {
       this.set(['commentRanges', index, 'hovering'], false);
     }
+
+    this._toggleRangeElHighlight(threadEl, /* highlightRange= */ false);
   }
 
   _indexForThreadEl(threadEl) {
diff --git a/polygerrit-ui/app/elements/diff/gr-ranged-comment-layer/gr-ranged-comment-layer.js b/polygerrit-ui/app/elements/diff/gr-ranged-comment-layer/gr-ranged-comment-layer.js
index 70aa1e7..9c9997c 100644
--- a/polygerrit-ui/app/elements/diff/gr-ranged-comment-layer/gr-ranged-comment-layer.js
+++ b/polygerrit-ui/app/elements/diff/gr-ranged-comment-layer/gr-ranged-comment-layer.js
@@ -133,10 +133,11 @@
     if (record.path === 'commentRanges') {
       this._rangesMap = {left: {}, right: {}};
       for (const {side, range, hovering} of record.value) {
-        this._updateRangesMap(
-            side, range, hovering, (forLine, start, end, hovering) => {
-              forLine.push({start, end, hovering});
-            });
+        this._updateRangesMap({
+          side, range, hovering,
+          operation: (forLine, start, end, hovering) => {
+            forLine.push({start, end, hovering});
+          }});
       }
     }
 
@@ -147,12 +148,13 @@
       // not the index, especially in polymer 1.
       const {side, range, hovering} = this.get(match[1]);
 
-      this._updateRangesMap(
-          side, range, hovering, (forLine, start, end, hovering) => {
-            const index = forLine.findIndex(lineRange =>
-              lineRange.start === start && lineRange.end === end);
-            forLine[index].hovering = hovering;
-          });
+      this._updateRangesMap({
+        side, range, hovering, skipLayerUpdate: true,
+        operation: (forLine, start, end, hovering) => {
+          const index = forLine.findIndex(lineRange =>
+            lineRange.start === start && lineRange.end === end);
+          forLine[index].hovering = hovering;
+        }});
     }
 
     // If comments were spliced in or out.
@@ -160,26 +162,40 @@
       for (const indexSplice of record.value.indexSplices) {
         const removed = indexSplice.removed;
         for (const {side, range, hovering} of removed) {
-          this._updateRangesMap(
-              side, range, hovering, (forLine, start, end) => {
-                const index = forLine.findIndex(lineRange =>
-                  lineRange.start === start && lineRange.end === end);
-                forLine.splice(index, 1);
-              });
+          this._updateRangesMap({
+            side, range, hovering, operation: (forLine, start, end) => {
+              const index = forLine.findIndex(lineRange =>
+                lineRange.start === start && lineRange.end === end);
+              forLine.splice(index, 1);
+            }});
         }
         const added = indexSplice.object.slice(
             indexSplice.index, indexSplice.index + indexSplice.addedCount);
         for (const {side, range, hovering} of added) {
-          this._updateRangesMap(
-              side, range, hovering, (forLine, start, end, hovering) => {
-                forLine.push({start, end, hovering});
-              });
+          this._updateRangesMap({
+            side, range, hovering,
+            operation: (forLine, start, end, hovering) => {
+              forLine.push({start, end, hovering});
+            }});
         }
       }
     }
   }
 
-  _updateRangesMap(side, range, hovering, operation) {
+  /**
+   * @param {!Object} options
+   * @property {!string} options.side
+   * @property {boolean} options.hovering
+   * @property {boolean} options.skipLayerUpdate
+   * @property {!Function} options.operation
+   * @property {!{
+   *  start_character: number,
+   *  start_line: number,
+   *  end_line: number,
+   *  end_character: number}} options.range
+   */
+  _updateRangesMap(options) {
+    const {side, range, hovering, operation, skipLayerUpdate} = options;
     const forSide = this._rangesMap[side] || (this._rangesMap[side] = {});
     for (let line = range.start_line; line <= range.end_line; line++) {
       const forLine = forSide[line] || (forSide[line] = []);
@@ -187,7 +203,9 @@
       const end = line === range.end_line ? range.end_character : -1;
       operation(forLine, start, end, hovering);
     }
-    this._notifyUpdateRange(range.start_line, range.end_line, side);
+    if (!skipLayerUpdate) {
+      this._notifyUpdateRange(range.start_line, range.end_line, side);
+    }
   }
 
   _getRangesForLine(line, side) {
diff --git a/polygerrit-ui/app/elements/diff/gr-ranged-comment-layer/gr-ranged-comment-layer_test.html b/polygerrit-ui/app/elements/diff/gr-ranged-comment-layer/gr-ranged-comment-layer_test.html
index ff1f4a7..37d1707 100644
--- a/polygerrit-ui/app/elements/diff/gr-ranged-comment-layer/gr-ranged-comment-layer_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-ranged-comment-layer/gr-ranged-comment-layer_test.html
@@ -214,11 +214,8 @@
 
     element.set(['commentRanges', 1, 'hovering'], true);
 
-    assert.isTrue(notifyStub.called);
-    const lastCall = notifyStub.lastCall;
-    assert.equal(lastCall.args[0], 10);
-    assert.equal(lastCall.args[1], 12);
-    assert.equal(lastCall.args[2], 'right');
+    // notify will be skipped for hovering
+    assert.isFalse(notifyStub.called);
 
     assert.isTrue(updateRangesMapSpy.called);
   });