Incorrect repainting when using scripted Tools

[eishiya]

When using a scripted tool that displays a tile preview, when the preview changes, only the area occupied by the map cells is redrawn, any bits of tiles that stuck out of this area are not redrawn:

(Here, 48x48 tiles are being used on a 32x32 grid, so there are 16px of tile that stick out at the top and right.)

---

This next one may or may not be a related issue, but I'm including it here because it may be related and its triggers are so unusual that I worry I'll forget about it.
When Undoing the action of a custom Tool, sometimes a smaller area than the cell/tile is repainted. In this gif, there are two separate Undos, notice how each one only repaints the lower 24x24 of the modified cell:

The area repainted seems to be affected by the size of the tile last drawn to the map, I've been able to get 16x16, 24x24, and the full 48x48 repainted by placing tiles of those sizes prior to performing this test. However, it's not entirely consistent and sometimes the issue just seems to get resolved after painting some tiles, and I haven't tracked down a reliable way to reproduce it. On Discord, Bjorn suggested it may be a caching issue.

---

The scripted tool I used in these gifs is available here if you want to test with it, but any scripted tool that previews tiles seems to be affected by at least the first issue.

[bjorn]

This is due to the tilesets missing from the preview map, since they do currently not get added automatically. I'll make it so that they are.

[eishiya]

It seems the fix is not quite 100%.

Wrote a script today that copies tiles from a source map open in the editor to a map created in the script, and from there to a destination map in the editor (to allow copying entire layers across maps). The tilesets are not added to the destination map.

The layer's tiles are added prior to the layer being added to the map, I recall you mentioned that potentially being a problem. However, the structure of the code is such that it would be messy to change the order. I think addLayer() should add any new tilesets to the map, if it doesn't already.