When you use the "Open…" command in Textastic, the operating system opens Textastic's sandbox so that it can access the file you choose in the document picker. Textastic does not have access to other files in the same folder, so the web preview screen does not show CSS or image files.

You could also use the Preview feature in Working Copy instead. It trivially has access to all the files and can include everything in its preview.

When Textastic invokes the document picker, it limits the types of files to the following system-declared uniform type identifiers: "public.text", "public.plain-text", "public.source-code" and "public.script". This is done because it cannot edit files such as image or video files.

The ".jl" file extension is by default not known to the system so there is no uniform type identifier declared for it. This means that document providers typically do not allow to open such a file.

The option is still the same in Textastic 6. I have attached a screenshot. Make sure to disable "Auto Word Wrap".

Please try to move the file "Symbol List - Heading.tmPreferences" into a subfolder called "Preferences".

I'm actually currently working on an "Open quickly"/"Go to file" feature with sophisticated fuzzy matching which will also include "go to line" functionality. I also hope to add print support, but it's not that easy because I'm using my own completely custom low-level text view.

Can you please try to reboot your device? It can often fix problems with the document picker.

You can use "Open In" to copy a file to another app: http://www.textasticapp.com/v6/manual/lessons/How_can_I_view_an_image_file_or_open_a_file_in_another_app.html

You can also use the Edit button in Textastic, select files and create a ZIP archive: http://www.textasticapp.com/v6/manual/lessons/How_can_I_move__copy_and_rename_files_and_folders.html