Another thing I noticed are the version and Bundle ID keys in the respective Info.plist files. NewPixaTool needs "1.57" as the CFBundleShortVersionString, and PixaTool needs "1.35". (The bundle versions, i.e. 1.0.0.0 and 1.0.25 can remain.) The CFBundleIdentifier keys need to have different values, namely (for example) "io.nwjs.nw.NewPixaTool" and "io.nwjs.nw.PixaTool"… otherwise you'll have two programs or processes with the same Bundle ID, and that's not a nice thing to do to macOS and its users. ;)