Right-click on Mac ...
.. is always, always a CTRL-click. (If you need ctrl-click under Linux/Win, you might want to change that to CMD-click on Mac.)
I guess this is an issue in ImGUI. There is some talk about a patch here: https://github.com/ocornut/imgui/issues/1765 But I could not find the exact changes that I could apply to the version that comes with SHADERed.
Afterthought: maybe there is one specific place in Shadered that checks for left click. At that point, maybe, one could check for the control key, and then generate a right-click event ... This might be easier to do than finding the right patches in ImGui or use different branch.
Mostly, I would be interested in accessing the context menu of a shader pass, so that I can access the uniforms GUI - there seems to be no other way than the right-click on the shader pass name.
There seems to be a branch of ImGUI that supposedly has the ctrl-click feature for Mac (in lieu of a right-click). That branch is named docker, but replacing the master source with this one when I compile ShaderEd does not work (some problem with tables).
If someone else can explain to me how to make it work, I'd appreciate it very much.