I know about that problem. It’s because the “last” modified tile “wins”. Let me explain…
With seamless tile painting, where your image is just one tile and you activate a patterned display using menu Processing/Enable Pattern Drawing, every change of every repeated copy of the tile is copied around.
In the tile mapping such a logic is not included. That means the enginge just looks for changes in the map from top left to right bottom. If it finds differences between the pixels on the map and an existing tile in the library it just copies all of the new tile contents from the map in into the tile library entry.
At the moment I’m working on different improvements for the tile map system and this is one of the topics. Other topics are:
- save project with sync mode off (already done)
- allow duplication mode for tile placement and tile modificateion (done)
- shortcut to switch between the edit modes (done)
- store library window open state (done)
- select/lock tile(s) to only modify the selected instances and protect all others (todo)
- RMB pick up to cut out tiles, RMB erasing with zero tile (done)
Having all this we should have a way more smoother work on tile sets.