diff --git a/addons/xterm-addon-webgl/src/WebglRenderer.ts b/addons/xterm-addon-webgl/src/WebglRenderer.ts
index 5d853f0f..e80464da 100644
--- a/addons/xterm-addon-webgl/src/WebglRenderer.ts
+++ b/addons/xterm-addon-webgl/src/WebglRenderer.ts
@@ -419,7 +419,6 @@ export class WebglRenderer extends Disposable implements IRenderer {
     if (this._workColors.fg & FgFlags.INVERSE) {
       if (bgOverride !== undefined && fgOverride === undefined) {
         // Resolve bg color type (default color has a different meaning in fg vs bg)
-        debugger;
         if ((this._workColors.bg & Attributes.CM_MASK) === Attributes.CM_DEFAULT) {
           fgOverride = (this._workColors.fg & ~(Attributes.RGB_MASK | FgFlags.INVERSE | Attributes.CM_MASK)) | ((this._colors.background.rgba >> 8 & 0xFFFFFF) & Attributes.RGB_MASK) | Attributes.CM_RGB;
         } else {
diff --git a/src/common/SortedList.test.ts b/src/common/SortedList.test.ts
index 5ecdbb77..ecafdb8f 100644
--- a/src/common/SortedList.test.ts
+++ b/src/common/SortedList.test.ts
@@ -74,9 +74,11 @@ describe('SortedList', () => {
     list.insert(8);
     list.insert(6);
     assertList([5, 5, 5, 6, 8, 8]);
+    deepStrictEqual(Array.from(list.getKeyIterator(1)), []);
     deepStrictEqual(Array.from(list.getKeyIterator(5)), [5, 5, 5]);
     deepStrictEqual(Array.from(list.getKeyIterator(6)), [6]);
     deepStrictEqual(Array.from(list.getKeyIterator(8)), [8, 8]);
+    deepStrictEqual(Array.from(list.getKeyIterator(9)), []);
   });
   it('clear', () => {
     list.insert(1);
diff --git a/src/common/SortedList.ts b/src/common/SortedList.ts
index 2112a73f..051c6702 100644
--- a/src/common/SortedList.ts
+++ b/src/common/SortedList.ts
@@ -3,6 +3,11 @@
  * @license MIT
  */
 
+/**
+ * A generic list that is maintained in sorted order and allows values with duplicate keys. This
+ * list is based on binary search and as such locating a key will take O(log n) amortized, this
+ * includes the by key iterator.
+ */
 export class SortedList<T> {
   private readonly _array: T[] = [];
 
@@ -47,6 +52,9 @@ export class SortedList<T> {
       return;
     }
     let i = this._search(key, 0, this._array.length - 1);
+    if (i < 0 || i >= this._array.length) {
+      return;
+    }
     if (this._getKey(this._array[i]) !== key) {
       return;
     }