Setting repository for elements

I am migrating a project from StarUML by using the "Create project from XMI" option.

I had organized my project in packages but when it was converted, all elements went into the "Model 1" folder.

I would like to have more folders but moving each element into the desired folder by using the Properties dialog would be a huge effort.

I can see that there is a "Move to folder" option on the right menu but I could not find out how to have it enabled.

Any suggestions for me?

Thanks.

Ramiro.