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In the next version, Textastic registers all supported file extensions in the system.

This way, the open in menu should show up on all supported files.
Well, the syntax highlighter is based on the open source text editor Fraise ( which is in turn based on Smultron.

The syntax highlighter uses simple plist files that contain information about keywords, strings, comments, keywords and so on.

If you find a syntax definition compatible with Fraise or Smultron it's really easy for me to support it in an update.

But it's easy to get the regular expressions in the syntax definition wrong so that it either hangs because the regular expression is too complex and takes too long to parse or it's just wrong and makes the app crash...

For the moment, I think it's better if I manually integrate new syntax files.
This is now implemented. Will be available in 1.1.

The user now has the option to show or hide the sidebar in landscape and even in portrait orientation. This way, everone can decide if he wants to see the sidebar or not.
The cursor position (selected range) is now saved - even between app launches.

Will be available in the next release.