Canvas context menu and also node context menu are overrideable, but when you click on slot you get only the build version.

I would like to see that could also be overriden.

When the browser zoom level is not 100%, right clicking in the Blockly workspace opens the browser context menu on top of the Blockly context menu.
I'm on Ubuntu 16.04.5 with Chrome 72.0.3626.81, but have also seen the issue on macOS Sierra Version 10.12.6 with Chrome 75.0.3770.100. See gif below.

![ardublockly-bug](https://user-images.githubusercontent.com/6350840/60499787-0cd5e680-9cb1-11e9-

I am trying to run Snap4Arduino (downloaded the binary from snap4arduino.rocks) om MacOS 10.13.1,
but I cannot be started. I get an error:
The application "Snap4Arduino.app" can't be started -47
How can the issue be resolved?

Please share your thoughts about the problem I described above and about possible solutions.

Problem

I would like to refine our coding style regarding RefCells. Recently I faced a problem I'd been afraid since I work here, namely a borrowing hell. That is my name for situation, where changes which look quite innocent cause panics in places seemingly unrelated to them.

For inst

At some places such as in aseba/compiler/compiler.cpp for method compile, the doxygen documentation of public methods is located in the cpp file. It would be better to put it in the header file (aseba/compiler/compiler.h), because the cpp file