I have just updated to Visual Studio 2026. When editing a PHP file, if I drag and drop some text, a copy of the text is made instead and the undo buffer is not updated, so it is impossible to undo. I experience exactly the same problem on two different computers, and I have observed it when editing any PHP file, but never with any other type of file.
I am using Visual Studio 18.5.1 and PHPTools 1.89.18735