Where is the Menu Editor?

It was removed to keep the UI consistent.

It was removed when the X series was rolled out years ago.

Tripecac, you really need to understand that the code base for the X series has many differences compared to 8.5. 8.5 had an insane amount of menu clutter. The solution was to allow you to modify it. The solution in the X series was to add sub-menus that are context-sensitive in the sense of moving purely track-oriented commands to the Track View. I think most users would agree that on balance, this is a better way of doing things and promotes a more streamlined workflow by showing options only in a context where they're relevant.
 
You are mistaken to think that this function was simply "taken out." The structure changed in the process of localizing menu choices. Therefore the way of implementing the function was no longer possible.
 
Next, note how many versions it took from SONAR 1.0 to include features that became part of 8.5. The X series will go through a similar evolution over time. It wouldn't surprise me if menu customization was added back in along a similar point on the program's trajectory, even though I think most people would consider it "nice, but not essential." Also as noted, because the structure is changed, it's not a question of adding something that already existed back in, but creating something new. VST3 support, ARA integration, and Windows 10 compatibility are new features that I believe are far more important for most people. 
 
The option to do user menu customization hasn't existed for quite some time, so if this is the first time you've discovered this and are therefore asking the question, it can't be all that important to you. There are reasons behind the decisions that are made and to assume that complaining about them will make a difference is highly unlikely. Feature requests, resources, more engineers, and a groundswell of support are more likely to make a difference over time.
 
 

why not use the customization module in the control bar ?
it can do almost anything the right click context menu can do and more.
there is sooo much ability to customize in sonar platinum.
 
I think what you may be running in to now is a learning curve of a new version of sonar.
for example the customization module. you don't even need to right click anything.
you just press a button. and you can customize these buttons for 100's of  different commands.
 
its not always about the limitations, its about how you work.
Sonar is not going to adapt to you, you have to adapt to it.
and if you don't want to adapt to it, your wasting your time.
 

Why not just go back to Sonar 8.5.3?

It also looks like workspace customization is in the planning stages. Have a look at the upcoming features for a bit more information.

Anderton

chuckebaby
its not always about the limitations, its about how you work.
Sonar is not going to adapt to you, you have to adapt to it.
and if you don't want to adapt to it, your wasting your time.

 
Sounds like an updated version of "God, grant me the serenity to accept the things I cannot change, courage to change the things I can, and wisdom to know the difference" - Reinhold Niebuhr 
 

ya I suppose I can get a little deep sometimes.