if fill in screen is activated, it will not spread beyond your screen's limit or select the area you want to be filled, and use bucket in selection, it will not spread beyond the selection or just lay temporary tiles to block where you do not want them to spread these ways would be much faster than using pencil all the way through anyways, for the bug, I cant find a way to make it happen... so i dunno what to fix =/ when it happens, try zooming in / out , see if it fixes the problem ; zooming re-sets the values of the scrollbars oh, and on the screenshot, where was the actual Pencil cursor pointing to? on the squared tile or on the preview tile? and if you lay the tile, it lays where the preview is? and you just made me think about something... there should be a tool option for the bucket: [] spread diagonally to make it not only check directly on the sides, but diagonally as well ; very useful to fill in between close diagonal walls