The "MsSql." prefix is displayed when it is not the default type set for the element.
You can change the default type set. Each diagram, folder and also the project has its default type set. Element default type set is defined by its repository (you can see it in the Properties dialog for element - field Repository).
Default type set for a project can be changed in Project Properties page, default type set for a folder can be changed in Folder Properties dialog and also default type set for a diagram can be changed this way. Open Project tree sidebar, right click on a node (project/folder/diagram) and choose Properties. In the displayed page/window, you can change the default type set to MS SQL.
A short tutorial with screenshots on this topic will be created soon.
Also the default type set concept will be analyzed whether it could be simplified.