You can just drag the file icon from Textastic's window title bar onto the other editor's dock icon. This will open the file in the other app while it is still open in Textastic.

In iOS 8 it will be possible for developers to create system-wide custom keyboards and distribute it through the App Store. I'm pretty sure someone will develop a Dvorak keyboard.

Sorry, but I don't plan to add more localizations at the moment.

Are you sure you are in the right support forum? This one is for the app "Textastic" which is only available for iOS and Mac. 

Can you reproduce it reliably?

This should already be the case.

I slightly changed the undo behavior in Textastic 3.0 which is currently waiting for review at Apple and should be available on the Mac App Store in a few days. Please let me know if the new version still has this problem once it is released.

I added it to version 3.0 of Textastic for Mac (currently waiting for review at Apple) and plan to add it to the iOS version. 

Thanks for the example file. The encoding routine didn't properly handle the standalone attribute that follows the encoding attribute in the XML header. 

This bug will be fixed in the next update.