If an item in a ComboBox drop down starts with a - (or other special Find Expression character) a Select By Text will fail, for example:
Overall Result: Fail
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'2/7/2014 2:00:33 PM' - Using .Net Runtime version: '4.0.30319.18408' for test execution. Build version is '2013.2.1327.0'.
'2/7/2014 2:00:33 PM' - Starting execution....
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'2/7/2014 2:00:34 PM' - Using 'E:\Users\Dad\Documents\Visual Studio 2010\Projects\WpfApplication1\WpfApplication1\bin\Release\WpfApplication1.exe' application.
'2/7/2014 2:00:35 PM' - 'Pass' : 1. Open 'ComboBox1Combobox' drop down.
'2/7/2014 2:00:36 PM' - 'Pass' : 2. Select by text 'First item' in ComboBox1Combobox
'2/7/2014 2:00:38 PM' - 'Pass' : 3. Open 'ComboBox1Combobox' drop down.
'2/7/2014 2:00:39 PM' - 'Pass' : 4. Select by text 'Second Item' in ComboBox1Combobox
'2/7/2014 2:00:40 PM' - 'Pass' : 5. Open 'ComboBox1Combobox' drop down.
'2/7/2014 2:00:41 PM' - 'Fail' : 6. Select by text '-Third Item' in ComboBox1Combobox
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Failure Information: 
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Unable to locate a ComboBox item by text '-Third Item'! Please make sure the special symbols are handled correctly (check ArtOfTest.Common.FindSpecialChars enum).
InnerException:
System.ArgumentException: Unable to locate a ComboBox item by text '-Third Item'! Please make sure the special symbols are handled correctly (check ArtOfTest.Common.FindSpecialChars enum).
   at ArtOfTest.WebAii.Controls.Xaml.Wpf.ComboBox.SelectItemByText(Boolean simulateRealUser, String text)
   at ArtOfTest.WebAii.Controls.Xaml.Wpf.ComboBox.SelectItemByText(Boolean simulateRealUser, String text, Boolean openDropDownBeforeSelection)
   at ArtOfTest.WebAii.Design.IntrinsicTranslators.Silverlight.Descriptors.ComboBoxSelectItemActionDescriptor.Execute(IApplication hostApp)
   at ArtOfTest.WebAii.Design.Extensibility.XamlActionDescriptor.Execute(IAutomationHost autoHost)
   at ArtOfTest.WebAii.Design.Execution.ExecutionEngine.ExecuteStep(Int32 order)
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'2/7/2014 2:00:41 PM' - Detected a failure. Step is marked 'ContinueOnFailure=False' aborting test execution.
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'2/7/2014 2:00:41 PM' - Overall Result: Fail
'2/7/2014 2:00:41 PM' - Duration: [0 min: 6 sec: 783 msec]
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'2/7/2014 2:00:41 PM' - Test completed!

The problem is that the - character is a special character that means find the item that is missing the specified text.

To manually work around this precede the SelectedText value with a ' character. This serves as an escape character and causes Test Studio to not try to interpret the following character. However this should not be required to be set after default recording.