How to move diagrams

Hey group,

I have trouble moving diagrams within the directory structure. For 
example I have several class diagrams. Now I would like to seperate them 
into different directories. So I created a directory A, B, C, etc. But 
when I now click a diagram in the tree view to drag it to the new 
directory nothing happens. When I try to cut and paste the diagram, I 
get the error that the data is of wrong format and cannot be pasted.

Does anyone have an idea what is going wrong? I'm running Platform 
Version 4.5.1.

Thanks for your help,

Torsten

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