Several people on this forum have been very helpful in clarifying how to overlay images to get a combined effect such as outlining a hexagonal tile with a highlighted color when the tile is selected.
Now I seem to have a different issue with such a process when I want a selected tile to be de-selected. In this case all of the code works fine but when a tile is redrawn after it has been de-selected, only the original base tile is draw without the highlighted overlay. What happens in this case is that it appears that a slight residue from the highlighted overlay appears to remain, though it was not drawn under these circumstances. Here are three images to demonstrate the issue...
No Tiles Selected
Three Tiles Selected
Three Tiles De-selected
Notice the slightly yellow residue from the original selection highlighting in the last image?
Any help with this issue will be greatly appreciated.