diff --git a/ext/fg/css/client.css b/ext/fg/css/client.css
index 16079a42..aefc2187 100644
--- a/ext/fg/css/client.css
+++ b/ext/fg/css/client.css
@@ -16,7 +16,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-iframe.yomichan-popup {
+iframe#yomichan-popup {
     all:        initial;
     border:     1px solid #999;
     box-shadow: 0 0 10px rgba(0, 0, 0, .5);
diff --git a/ext/fg/js/client.js b/ext/fg/js/client.js
index 7e9a9896..303f959b 100644
--- a/ext/fg/js/client.js
+++ b/ext/fg/js/client.js
@@ -87,6 +87,8 @@ class Client {
             return;
         }
 
+        range.setLength(this.options.scanLength);
+
         if (this.lastRange !== null && this.lastRange.equals(range)) {
             return;
         }
@@ -113,7 +115,7 @@ class Client {
         this.popup.showNextTo(range, content);
 
         if (this.options.highlightText) {
-            this.range.select(length);
+            range.select(length);
         }
 
         this.lastRange = range;
diff --git a/ext/fg/js/popup.js b/ext/fg/js/popup.js
index 694aa6b7..4c5a01d8 100644
--- a/ext/fg/js/popup.js
+++ b/ext/fg/js/popup.js
@@ -49,8 +49,8 @@ class Popup {
             posY = elementRect.top - popupRect.height - this.offset;
         }
 
-        this.popup.style.left       = pos.x + 'px';
-        this.popup.style.top        = pos.y + 'px';
+        this.popup.style.left       = posX + 'px';
+        this.popup.style.top        = posY + 'px';
         this.popup.style.visibility = 'visible';
 
         this.setContent(content);
diff --git a/ext/fg/js/range.js b/ext/fg/js/range.js
index cf568a9c..85430a7b 100644
--- a/ext/fg/js/range.js
+++ b/ext/fg/js/range.js
@@ -35,16 +35,16 @@ class Range {
             return null;
         }
 
-        range.setEnd(node, offset + length);
+        this.range.setEnd(node, offset + length);
         return length;
     }
 
     containsPoint(point) {
-        const rect = this.paddedRect();
+        const rect = this.getBoundingClientRect();
         return point.x >= rect.left && point.x <= rect.right;
     }
 
-    paddedRect() {
+    getBoundingClientRect() {
         const range       = this.range.cloneRange();
         const startOffset = range.startOffset;
         const endOffset   = range.endOffset;
@@ -72,8 +72,8 @@ class Range {
 
     equals(range) {
         const equal =
-            range.compareBoundaryPoints(Range.END_TO_END, this.range) === 0 &&
-            range.compareBoundaryPoints(Range.START_TO_START, this.range) === 0;
+            range.range.compareBoundaryPoints(Range.END_TO_END, this.range) === 0 &&
+            range.range.compareBoundaryPoints(Range.START_TO_START, this.range) === 0;
 
         return equal;