Thanks for letting me know about the issue!

This is fixed in Textastic 10.8.6 which was released today.

This is fixed in Textastic 10.8.6 which was released today.

Can you please try if a restart of your device fixes that issue?

On my iPhone running iOS 26.1, that triple finger menu is displayed differently, not as in your screenshot. 

Here is a screenshot:

Good news! With the help of another developer, I found a way to tell the system that it should open files in the same window instead of creating a new one.

So this will be fixed in the next update.

I've debugged this issue on iPadOS 26.1: the system creates a new window (UIWindowScene) before telling Textastic to open the file.

I've tried various ways to prevent creation of a new window, but unfortunately I found no workaround.

So, this looks like a new system behavior on iPadOS 26.1 that cannot be changed by Textastic.

I also see the same issue when opening a file with other apps like iA Writer, Taio or Runestone.

Hopefully Apple changes this in a future update.

I can reproduce the issue on my iPad. I'll try to find out what's going on. This definitely behaved differently in earlier iPadOS versions.

As a workaround, please use the "Open…" command in Textastic to open files from the Files app in the current window. Or use "Add External Folder…" to add a folder from the Files app to Textastic's sidebar (if supported by the file provider).