Error closing Toad after using Optimizer: "System.OutOfMemoryException: Exception of type 'System (4223899)

The following error occurs when closing Toad. This error only occurs when opening multiple Optimzier windows within Toad and tuning a few queries:

System.OutOfMemoryException: Exception of type System.OutOfMemoryException was thrown.

Stack trace:

at System.String.GetStringForStringBuilder(String value, Int32 startIndex, Int32 length, Int32 capacity)
at System.Text.StringBuilder.GetNewString(String currentString, Int32 requiredLength)
at System.Text.StringBuilder.Append(Char[] value, Int32 startIndex, Int32 charCount)
at System.IO.StreamReader.ReadToEnd()
at Quest.Toad.Gui.MainForm.SaveCustomization(XmlNode root)
at Quest.Toad.Gui.MainForm.SaveSession(SessionSettings session)
at Quest.Toad.Gui.MainForm.MainForm_Closing(Object sender, CancelEventArgs e)...


Issue is persistent even with all Optimizer windows and Toad windows are closed prior to closing Toad.