Your comments

I use the official Dropbox API. It uses HTTPS for things like login and downloading files. It uses HTTP for less critical files like loading metadata and sending command to create folders or move files. I don't intend to change that.
On Windows, there is Sublime Text and E Text Editor which you can use to test themes.
Hello,

please enable the "Debug Log" setting for the connection to create a log file. Maybe having a look at the log file helps to find out the cause of the problem.
I just tried it on my iPad with iOS 5 and I can't reproduce it. Is there something special about your file?
Super, danke fürs Review!

It sounds like your SSH server doesn't have SFTP enabled. You can probably find out more by having a look at the server configuration file or at the server log file. 


Public key support is explained in the manual at http://www.textasticapp.com/v3/manual/lessons/How_do_I_connect_to_an_FTP__FTPS_or_SFTP_server.html#step_5
They claim to approve 99% within 7 days.

The last update took only a day to approve. I've submitted an update for another app yesterday which was approved within 2 hours (!!). This update seems to take a little longer. It's still "Waiting for review", but well within the 7 days period.
If you *really* want to make sure that you get disconnected: if you change FTP settings and tap on the "Done" button in the connection configuration screen, all connections are closed so that the new settings are used the next time you connect.
Yes, I plan to implement something like this in a future version. Maybe depending on the current file context.
You don't need to. Textastic will automatically open and close connection as it needs to.

In settings you can set the maximum amount of connections Textastic uses. The default for FTP is 3.