I just installed 1.0.0.51 and tested the option to sort resx file content by key. It seems that the '_' character is incorrectly sorted last when it should be listed first as follows:
<data name="Select_Input_Images" xml:space="preserve">
<value>Select Input Images</value>
</data>
<data name="SelectLanguage" xml:space="preserve">
<value>Please select a language.</value>
</data>
<data name="Select_Input_Images" xml:space="preserve">
<value>Select Input Images</value>
</data>
<data name="SelectLanguage" xml:space="preserve">
<value>Please select a language.</value>
</data>