I'm sorry, but per-file read-only mode is a very specific feature request that I think most users won't need.

Dropbox disabled their old API. I added support for the new Dropbox v2 API in Textastic 6.3.2 in April last year.

You are still using Textastic 5.3.1. 

Textastic 6 is the first paid upgrade since version 1.0 was released in 2010. 

Implementing split view multitasking, making the app universal and supporting iPad Pro required a rewrite of large parts of the app. Charging for Textastic 6 allows me to continue to dedicate resources to improving it.

Among other features, Textastic 6.1 added Google Drive remote connections. Textastic 6.2 added new fonts and the ability to open Git repositories from Working Copy as external folders. Emmet support and a JavaScript console was added in Textastic 6.3. Textastic 6.4 adds support for iOS 11.

You can purchase Textastic 6 on the App Store: https://itunes.apple.com/us/app/id1049254261?ct=support&at=11lNQP&pt=15967&mt=8

Hello,

the main editor currently does not support spell checking. The menu in your screenshot is a standard macOS menu. It is active when the cursor is in a text field (for example in a search text field), but not when the editor is active.

You can add custom syntax definitions to Textastic by using TextMate bundles. See
http://www.textasticapp.com/v6/manual/lessons/How_can_I_add_my_own_syntax_definitions__themes_and_templates.html

A search for "netlogo tmbundle" in Google brought up this TextMate bundle which should work:

https://github.com/textmate/logo.tmbundle

I'm not familiar with Netlogo, so I'm not sure how well the Logo bundle works for you. After installing the bundle in Textastic, you should be able to select a "Logo" syntax definition after opening a file.

I'll look into it. In previous iOS versions this wasn't possible, but maybe something changed there.

Hello, you can only select files from Dropbox, not folders. Selecting folders only works if the files in the providing app are stored locally - like in Working Copy.

To download entire folders into Textastic, you can use Textastic's built-in Dropbox support: https://www.textasticapp.com/v6/manual/lessons/How_do_I_access_files_in_my_Dropbox_account.html

Ok, I thought you could not connect to Dropbox at all.

I have no reports from other users that there is a general problem like this, so there must be something special about the files in your Dropbox account that causes this problem.

You mention the amount of files. How many files and subfolders do you have in the folder you try to open? Are there maybe any special file names?

It's hard for me to reproduce without additional details.

Please tap on the circled "i" next to the Dropbox connection and check if it says "Linked". If it isn't linked, please tap on the row to link the connection to your Dropbox account.