Project already exists in the workspace

In SoapUI Pro: I have 2 projects I use in a workspace; they are very similar (but not exactly the same):  Project1 and Project2.  I cannot open both of them without answering a prompt.  Why does this happen?

1.  I created Project1 first.  Then I saved it and removed it from the workspace.  
2. To create Project2 - I imported Project1, renamed it (from Project1 to Project2 and renamed some of the test cases/steps), and saved it to a different location (on my harddrive).
3.  Now, whenever Project2 is opened in the workspace - if I try to import or open Project 1, I get a popup saying "This project already exists in the workspace."  I can choose "Import project again" so that I can have both Project1 and Project2 open in the workspace simultaneously. But what is the reason for this?  And can it be avoided?  I thought that renaming the 're-imported' project (and saving it to a different location) would be enough for SoapUI to recognize that Project1 and Project2 are 2 different projects.