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>
Comments: ** Comment from web user: tomenglert **
<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>
Comments: ** Comment from web user: tomenglert **
ResXManager is handling escaping exactly the same way as the built in resource editor.
If you fully read the articles you have mentioned you will find this:
http://www.w3.org/TR/xml11/#syntax
=> To allow __attribute values__ to contain both single and double quotes, the apostrophe or single-quote character (') __may__ be represented as " ' ", and the double-quote character (") as " " ".