Sometimes, when the left mouse button is released, the icon editor mistakenly thinks that the right mouse button has been clicked and draws a transparent pixel.
Fixed in 1.2.0. Editor now has an explicit check for right mouse button clicks, rather than assuming that all clicks other than left is right (such as third button clicks).
Sometimes, when the left mouse button is released, the icon editor mistakenly thinks that the right mouse button has been clicked and draws a transparent pixel.