Cannot open edmx file - ADO.NET Entity Data Model Designer missing "Open With"

I'm using VS 2008, Service Pack 1. Cannot ope开发者_开发知识库n edmx file in ADO.NET Entity Data Model Designer. When click open with I don't have even options to open with it.

The interesting thing it was working fine before.

I reinstalled service pack, reset settings - didn't help.

Any ideas how to fix it?

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This is also covered here: Entity Designer missing

It may be faster for you to uninstall and reinstall VS, than trying to find out what the problem is.