[KBM] Prevent keyboard manager crash when index is not found (#6488)

* Added Sleep(5000) for repro

* Added check to prevent kbm crash for index not found

* Add more safeguards

src/modules/keyboardmanager/ui/ShortcutControl.cpp

@@ -104,11 +104,24 @@ void ShortcutControl::AddNewShortcutControlRow(Grid& parent, std::vector<std::ve
         // Get index of targetAppTextBox button
         UIElementCollection children = parent.Children();
         uint32_t index;
-        children.IndexOf(targetAppTextBox, index);
+        bool indexFound = children.IndexOf(targetAppTextBox, index);
+
+        // IndexOf could fail if the the row got deleted after LostFocus handler was invoked. In this case it should return
+        if (!indexFound)
+        {
+            return;
+        }
+
         uint32_t lastIndexInRow = index + ((KeyboardManagerConstants::ShortcutTableColCount - 1) - KeyboardManagerConstants::ShortcutTableTargetAppColIndex);
         // Calculate row index in the buffer from the grid child index (first set of children are header elements and then three children in each row)
         int rowIndex = (lastIndexInRow - KeyboardManagerConstants::ShortcutTableHeaderCount) / KeyboardManagerConstants::ShortcutTableColCount;
 
+        // rowIndex could be out of bounds if the the row got deleted after LostFocus handler was invoked. In this case it should return
+        if (rowIndex >= keyboardRemapControlObjects.size())
+        {
+            return;
+        }
+
         // Validate both set of drop downs
         KeyDropDownControl::ValidateShortcutFromDropDownList(parent, keyboardRemapControlObjects[rowIndex][0]->getShortcutControl(), keyboardRemapControlObjects[rowIndex][0]->shortcutDropDownStackPanel.as<StackPanel>(), 0, ShortcutControl::shortcutRemapBuffer, keyboardRemapControlObjects[rowIndex][0]->keyDropDownControlObjects, targetAppTextBox, false, false);
         KeyDropDownControl::ValidateShortcutFromDropDownList(parent, keyboardRemapControlObjects[rowIndex][1]->getShortcutControl(), keyboardRemapControlObjects[rowIndex][1]->shortcutDropDownStackPanel.as<StackPanel>(), 1, ShortcutControl::shortcutRemapBuffer, keyboardRemapControlObjects[rowIndex][1]->keyDropDownControlObjects, targetAppTextBox, true, false);
@@ -164,7 +177,14 @@ void ShortcutControl::AddNewShortcutControlRow(Grid& parent, std::vector<std::ve
         uint32_t index;
         // Get index of delete button
         UIElementCollection children = parent.Children();
-        children.IndexOf(currentButton, index);
+        bool indexFound = children.IndexOf(currentButton, index);
+
+        // IndexOf could fail if the the row got deleted and the button handler was invoked twice. In this case it should return
+        if (!indexFound)
+        {
+            return;
+        }
+
         uint32_t lastIndexInRow = index + ((KeyboardManagerConstants::ShortcutTableColCount - 1) - KeyboardManagerConstants::ShortcutTableRemoveColIndex);
         // Change the row index of elements appearing after the current row, as we will delete the row definition
         for (uint32_t i = lastIndexInRow + 1; i < children.Size(); i++)

src/modules/keyboardmanager/ui/SingleKeyRemapControl.cpp

@@ -138,7 +138,14 @@ void SingleKeyRemapControl::AddNewControlKeyRemapRow(Grid& parent, std::vector<s
         uint32_t index;
         // Get index of delete button
         UIElementCollection children = parent.Children();
-        children.IndexOf(currentButton, index);
+        bool indexFound = children.IndexOf(currentButton, index);
+
+        // IndexOf could fail if the the row got deleted and the button handler was invoked twice. In this case it should return
+        if (!indexFound)
+        {
+            return;
+        }
+
         uint32_t lastIndexInRow = index + ((KeyboardManagerConstants::RemapTableColCount - 1) - KeyboardManagerConstants::RemapTableRemoveColIndex);
         // Change the row index of elements appearing after the current row, as we will delete the row definition
         for (uint32_t i = lastIndexInRow + 1; i < children.Size(); i++)