WORKAROUND FROM THE TECHNICAL SUPPORT
There are easier ways to perform simultaneous evaluations in Mathematica, with notebooks that remain in separate contexts, all within a single instance of the Front End.
First, we will explore how you can access more kernels from your current session, allowing simultaneous evaluation in separate notebooks:
- In a notebook, go to Evaluation -> Kernel Configuration Options from the toolbar.
- Click Add
- Name the secondary kernel, and ensure that "Local Machine" is checked.
- Press OK
Now in a notebook, if you go to Evaluation -> Notebook's Kernel -> select your new kernel, it will do its evaluations outside of the local kernel that opens by default. Now, you are able to perform simultaneous evaluations on two notebooks.
You can read more about this here, under Details:
To remove a notebook from the Global` context, you can go to Evaluation -> Notebook's Default Context -> Unique to this Notebook.
Combining these two processes should give you results identical to a notebook that you would have by simultaneously opening two Front Ends -- without the strain on your machine of having two Front Ends running.
While it is not ideal, it is what I am currently able to provide as a workaround to this particular issues in version 10.4.