Currently, it's not possible to adjust the light height, sorry.

Please try the following to import an image from the photo library: 

• go to a directory in Local Files or iCloud
• tap on the "+" button in the bottom toolbar
• select "Image"
• pick an image from the photo library
• enter a file name
• tap "Done"

There's a read-only option in Textastic's settings that disables the keyboard so that you cannot modify a file. Please double-check that this setting is disabled.

Please try to select "PHP" as the syntax definition in the File Properties.

Yes, currently this is a two-step process. I'll consider letting you select a target directory when copying a file.

It is still on my todo list but didn't make it into version 7.0. I hope I can add it into one of the next versions.

Good point, this could certainly be improved.

This is not really related to the filtering. When you open a file from the list of files, it is opened in a transient tab, indicated by the italic title. When you then tap on another file, that file replaces the transient tab.

To make a tab stay when you open another file, tap on the file title or the pin button at the right side of the transient tab, or tap on the editor to bring up the keyboard.

This behavior is very similar to what you see in desktop editors such as Sublime Text, VS Code and Atom. It prevents you from opening too many tabs when browsing the files in a project. 

If you tap on the editor in landscape on iPhone to bring up the keyboard, the blue bars should already disappear (same as in portrait). Is that not the case for you?

I think that's covered by XML.