The command makes all pixels with a specified color in the current layer transparent. For more details see Τμήμα 8.57, «Χρώμα σε άλφα…».
This command only works on a single layer.
You can access this command
From the main menu through → → .
From the main menu through → (see Τμήμα 8.57, «Χρώμα σε άλφα…»).