Open new morph matrix while editing/creating a solution

If you start editing or creating a solution, and then open a new morph-file a breaking crash occurs.

+ Create a solution
+ Before saving it, load a new morph-file (preferably one that contains solutions)
+ Look at console log

**Possible solution:**
Perhaps the method that loads a new morph-file should check the WIM in State.js and ensure that it is "default" before doing anything.