Can you provide a bit more information as to exactly what happens when you try and access and edit the test steps? It appears to me that v2.7.0 seems to display a lot of similar erroneous behaviour when nothing visible appears to happen when attempting to access certain functionality. I've noticed issues launching my Preferences, Get Data in certain situations, attempting to browse to files (via Datasource step, adding properties files, etc.)
When you attempt to access the JDBC step, are you seeing anything in the logging? I see errors being reported when i see this dodgy behaviour.
if this helped answer the post, could you please mark it as 'solved'? Also if you consider whether the title of your post is relevant? Perhaps if the post is solved, it might make sense to update the title of the post to something more descriptive? This will help people when searching for problems.