Grid in tile palette window does not extend to edge of viewport

[2D] Grid in tile palette window does not extend to edge of viewport

Grid in tile palette window does not extend to edge of viewport when the palette is zoomed out and the window aspect ratio is different than the palette size

Steps to reproduce:

1. Import Top down Garden Castle.aseprite and set import mode to Tile Set
2. Open Tile Palette window and select Top down Garden Castle as active palette
3. Zoom the palette view out and with the tile palette window in a vertical orientation
4. Observe grid does not extend to end of the viewport

Actual results: Palette grid does not extend to end of the viewport

Expected results: Palette grid should extend to end of the viewport regardless of tile palette window orientation of aspect ratio

Tested on (OS): Windows 11