Has anyone here attempted to merge this project's functionality with MaximGB's TreeGrid, or know how to proceed with this? Having the tree level frozen while scrolling horizontally would be hugely useful (Excel has similar functionality) but I'm guessing it would be somewhat involved. https://extjs.com/forum/showthread.php?t=37831
Cool! It works on 2.2. One small bug: when scrolling to the bottom, there's a difference in pixels between the first column and the rest. It's probably caused by the scroll bar which introduces some suplementary space - not taken into account.
For the grid with frozen column if forcefit is set to false and the column width matches the grid width, I wonder if the left grid would get that extra space for horizontal scrollbar but not actually show it. It may solve the mismatch then scrolled down to the bottom.