You can discern folders from files not only by the icon, but also by the gray chevron on the right side of the folder name and the fact that it doesn't have a time stamp and file size.

Safari uses very similar icons with the same color for folders and bookmarks in its bookmarks list.

I don't plan to change that sorry. 

Yes, you are right. Remote file information is only saved when there was no error during the upload. This will be fixed in the next update.

Unfortunately, the transition to 64-bit in the latest version of Textastic introduced a bug on 32-bit devices (i.e. everything but iPad Air, iPad mini Retina and iPhone 5s): on these devices, the file size is passed incorrectly to the FTP library.

In my tests, the file was uploaded correctly, you would just get the "partial upload" error message. You can ignore that.

This will be fixed in the next update. I'm very sorry for the inconvenience.

I can't seem to reproduce it anymore even when repeating operations, sorry.

Are you doing the same as shown in your video, but just several times or are you doing something differently?

The code editor itself doesn't currently have spellcheck support, sorry. The "Spelling and Grammar" menu is for text fields like the Find and Replace text fields.

Textastic 5.1 now uses MultiMarkdown v4 instead of the Discount Markdown library for its integrated Markdown preview.

.mmd files automatically use the MultiMarkdown syntax highlighter, but you can also choose the syntax definition manually from the File Properties popover if you want to use it for other file extension like .md, which uses the Markdown syntax definition by default.

Textastic 5.1 now uses MultiMarkdown v4 instead of the Discount Markdown library.

How did you open the same file twice? This shouldn't be possible. Are you sure that it was indeed the same file?