Currently known issues with LifeViewer's drawing and selection functions.
Some patterns cannot be moved towards the edge of the grid even when sufficient room exists.
For the following example, Select All then attempt to move it to the left. This will be stopped despite there being enough room, as well as the fact that rotation can move cells into this region.
Rotating the pattern 90 degrees and attempting to move it vertically will also display an error.
Drawing limitations can be offset on some bounded grids in the Margolus neighbourhood.
In the following example, it's possible to start drawing by clicking on the bottom boundary or the right boundary. This is not normally possible.
It is also not possible to start drawing from the topmost row or leftmost column inside of the bounded grids. In order to draw here, the cursor must first be dragged further in bounds, or the click must start further in bounds.
In the general-range algorithm, selections behave oddly at the very edge of the unbounded grid.
For range 1 in the general range algorithm, the three cells at the edge are effectively treated as one. Any selection in a cell one or two away from the edge will snap to the very edge, and any selection containing any of those cells plus cells four or more cells away will select all three of those cells.
Since the three cells at the very edge cannot be modified at all, it'd be preferable if selections simply could not be made at the three cells at the edge for this algorithm. The fact that selections can be made here at all can result in unwanted deletion of cells when flipping or rotating selections containing them.