if one puts a line like:

aaaaaaaaa-aaaaaaaaaa

in the edit box, then double clicks to highlight the line...

either the right part, or the left part or the - only is highlighted... Is this normal to see the - as a separator for highlighting ?

That appears to be normal behavior for many/most text fields. Spaces and other "separating" characters will affect how text is highlighted. If you triple click it should get everything. Some times getting everything to get selected can be a pain and hitting ctrl+a is easier in my opinion.

Just try doing the same thing in the url bar of your browser or other places and you'll probably notice the same behavior.

Thanks for the fast response! Passing answer on to user who asked on the network I am on