Locator maps placed in item frames that are in blocks corresponding to the pixels on the left and top edges of the map do not show a green indicator. For example, a level 0 locator map centered at (0,0) maps the blocks from (-64,-64) to (63,63). It should display a green dot indicator if mounted in an item frame anywhere within that square of blocks. However, if placed in an item frame located anywhere from (-64,-64) to (63,-64) (the northern edge of the mapped area) or from (-64,-64) to (-64,63) (the western edge), it will not display the green indicator.

Note: This bug is probably the result of confusing the center point of the map with the block having the same coordinates. The block itself is to the east and south of the center point. If it is treated as the center of a square of blocks, that square must have an odd number of blocks on a side, so for a level 0 map with center (0,0) the mapped area would range from (-63,-63) to (63,63), which is the area within which the green indicator actually does appear. But this is incorrect logic, because a map always covers a square of blocks with an even number of blocks on a side.

Steps to reproduce:

1. In any convenient world, go to coordinates (0,0).
2. Activate a locator map.
3. Move to (3,-64).
4. Place a solid block at (3,-65), then place an item frame on it at (3,-64).
5. Place a copy of the map in the item frame.
6. Notice that the map does not display a green indicator.
7. Destroy the map, then move to (-64,5).
8. Place a solid block at (-63,5), then place an item frame on it at (-64,5).
9. Place a copy of the map in the item frame.
10. Notice that the map does not display a green indicator.

Expected results:
The map displays a green indicator because the item frame in which it's mounted is within its mapped area.

Observed results:
No green indicator appears on the mounted map.