Problems selecting objects

 From:  JTB
A video showing my problem with a simple example...What can cause this?

A simple rectangle and I use separate.... Then I can only select 3 of 4 lines... No matter how I create things, I have sometimes to try to another view to select some objects... For example the 4rth line can be selected in 3dview

***There is always a better way to do things... Just find your Moment of Inspiration***