I have divided the main window divided into 3-columns and I open files in the different columns. I used to be able to click on a file tab and drag the file to any of the other columns. At some point this changed such that I can only drag files between the first 2-columns (counting left to right). When I try to drag a file to the 3rd column, it won't go in the column, it just creates its own floating edit window.
I'm currently using v25.0.2.0 (64bit), but version 25.0.1.0 acted the same way.