Works absolutely fine when it comes to the normal placement filling (replacing air with block).
Has 2 issues remaining if you **replace fill an existing block with another one**
# Issue 1
If you completely undo the replacement fill steps (so it's back at the very beginning), the next fill step you do will not replace the first block where the fill tool has been set. Really trivial as the next step after that will fill/replace it just fine.
{F20399}
# Issue 2
Step is set incorrectly, just like in the description if you:
# do 2 fill steps
# undo
# redo
# undo
do another fill step and it puts it on the wrong spot does it at the wrong spot.
I do **not** notice this issue if i replace air blocks with the fill tool, only happens when they're replacing real blocks.