When using the ploygonal lasso in CC I find I cannot complete a selection without the lasso completing itself accross the proposed selection area.Did not experience this with CS6 -Have I got a setting wrong?
Also how do I load in my plug ins particularly Nik software?
You need to get updated plug-ins from the vendors. Just using older versions can be all sorts of messy and even cause crashes. Your lasso issue may be another matter, but without system info or some idea about what files you are working on nobody can't realyl tell you much. This could simply be an hardware acceleration issue when the tool try to detect auto-pan scenarios and a delay closing the selection or something like that. As a minor, check your prefs for that and update your graphics driver if possible.