I could reproduce the error and fixed it with dup(). Copying over the values makes sense, because they serve as the model portion for the variable view. Of course, it would be better to reuse the variables allocated by octave, but since accessing them is not thread-safe there is not other way of doing this. I saw you have implemented another model struct about the model portion (a "metamodel"), but that does not solve the issue, it's just replicating what we already have (a model part). You simply stored just a few infos about the variable, but not the value, so the value is not accessible (or only available at request, but then it needs to be copied anyways when requested) - but I want that :)
You see, there are currently only two real options that solve the issue without sustaining a loss in functionality:
1.) Octave guarantees threadsafe access, so its data can be used as a model portion. Advantage: Saves memory in Quint. Disadvantage: Will be slower even if thread-safety is not needed in Octave.
2.) Quint does a deep copy. Advantage: Octave performs fast. Disadvantage: Quint requires more memory.
I rather go for solution 2.).
As for the windows: History, Workspace and FileView can each be switched off by right clicking on the title and checking them off. I have reverted my changes to make everything dockable again in the current branch since many things were not working correctly. As the Qt docs say (http://doc.qt.nokia.com/latest/qmainwindow.html), having not a central widget is not supported. However I assigned it a dummy widget, but that caused problems when restoring the window state at startup, even when I assigned proper object names. What we really need here is an MDI: http://doc.qt.nokia.com/latest/qmdiarea.html