diff --git a/layout/generic/nsFrame.cpp b/layout/generic/nsFrame.cpp
index 48cbfd83108e..21a49e321361 100644
--- a/layout/generic/nsFrame.cpp
+++ b/layout/generic/nsFrame.cpp
@@ -4989,8 +4989,11 @@ NS_IMETHODIMP nsFrame::HandleDrag(nsPresContext* aPresContext,
 
   AutoWeakFrame weakThis = this;
   if (NS_SUCCEEDED(result) && parentContent) {
-    frameselection->HandleTableSelection(parentContent, contentOffset, target,
-                                         mouseEvent);
+    result = frameselection->HandleTableSelection(parentContent, contentOffset,
+                                                  target, mouseEvent);
+    if (NS_WARN_IF(NS_FAILED(result))) {
+      return result;
+    }
   } else {
     nsPoint pt = nsLayoutUtils::GetEventCoordinatesRelativeTo(mouseEvent, this);
     frameselection->HandleDrag(this, pt);
diff --git a/layout/generic/nsFrameSelection.cpp b/layout/generic/nsFrameSelection.cpp
index aefdaf4f127e..ec84d6c3bc46 100644
--- a/layout/generic/nsFrameSelection.cpp
+++ b/layout/generic/nsFrameSelection.cpp
@@ -1395,8 +1395,11 @@ nsresult nsFrameSelection::TakeFocus(nsIContent* const aNewFocus,
         // Start selecting in the cell we were in before
         nsINode* parent = ParentOffset(mTableSelection.mCellParent, &offset);
         if (parent) {
-          HandleTableSelection(parent, offset, TableSelectionMode::Cell,
-                               &event);
+          const nsresult result = HandleTableSelection(
+              parent, offset, TableSelectionMode::Cell, &event);
+          if (NS_WARN_IF(NS_FAILED(result))) {
+            return result;
+          }
         }
 
         // Find the parent of this new cell and extend selection to it
@@ -1408,8 +1411,11 @@ nsresult nsFrameSelection::TakeFocus(nsIContent* const aNewFocus,
         if (parent) {
           mTableSelection.mCellParent = cellparent;
           // Continue selection into next cell
-          HandleTableSelection(parent, offset, TableSelectionMode::Cell,
-                               &event);
+          const nsresult result = HandleTableSelection(
+              parent, offset, TableSelectionMode::Cell, &event);
+          if (NS_WARN_IF(NS_FAILED(result))) {
+            return result;
+          }
         }
       } else {
         // XXXX Problem: Shift+click in browser is appending text selection to
diff --git a/layout/generic/nsFrameSelection.h b/layout/generic/nsFrameSelection.h
index 01dfd4f7f816..351d03b595d8 100644
--- a/layout/generic/nsFrameSelection.h
+++ b/layout/generic/nsFrameSelection.h
@@ -284,7 +284,7 @@ class nsFrameSelection final {
    * and what keys are pressed
    */
   // TODO: replace with `MOZ_CAN_RUN_SCRIPT`.
-  MOZ_CAN_RUN_SCRIPT_BOUNDARY nsresult
+  [[nodiscard]] MOZ_CAN_RUN_SCRIPT_BOUNDARY nsresult
   HandleTableSelection(nsINode* aParentContent, int32_t aContentOffset,
                        mozilla::TableSelectionMode aTarget,
                        mozilla::WidgetMouseEvent* aMouseEvent);
@@ -817,7 +817,7 @@ class nsFrameSelection final {
     // (according to GetFirstCellNodeInRange).
     nsRange* GetNextCellRange(const mozilla::dom::Selection& aNormalSelection);
 
-    MOZ_CAN_RUN_SCRIPT nsresult
+    [[nodiscard]] MOZ_CAN_RUN_SCRIPT nsresult
     HandleSelection(nsINode* aParentContent, int32_t aContentOffset,
                     mozilla::TableSelectionMode aTarget,
                     mozilla::WidgetMouseEvent* aMouseEvent, bool aDragState,