[DevTools] Storage inspector throws an error when use arrow keys

Issue #102

1 files changed, 8 insertions, 1 deletions

diff --git a/devtools/client/shared/widgets/TableWidget.js b/devtools/client/shared/widgets/TableWidget.js
index a0f0dfc11..57d2914d5 100644
--- a/devtools/client/shared/widgets/TableWidget.js
+++ b/devtools/client/shared/widgets/TableWidget.js
@@ -463,7 +463,14 @@ TableWidget.prototype = {
       return;
     }
 
-    let selectedCell = this.tbody.querySelector(".theme-selected");
+    // We need to get the first *visible* selected cell. Some columns are hidden
+    // e.g. because they contain a unique compound key for cookies that is never
+    // displayed in the UI. To do this we get all selected cells and filter out
+    // any that are hidden.
+    let selectedCells = [...this.tbody.querySelectorAll(".theme-selected")]
+                                      .filter(cell => cell.clientWidth > 0);
+    // Select the first visible selected cell.
+    let selectedCell = selectedCells[0];
     if (!selectedCell) {
       return;
     }