vs 2015 with ssdt, copied .dtsx file won't start

Hi,   We have been using vs 2012/vs 2008 in the past and have always found that copying a .dtsx file to a different name and editing it seemed to work.   We are trying this with vs 2015 and ssdt and I'm running into problems.  We are trying to share one solution file amoungst many .dtsx file and I'm pretty sure that's not working.   Now when I copy a .dtsx file and try to edit it with vs 2015/ssdt it edits, it Builds, but it won't run or start.   I know we probably shot ourselves in the foot here but any thoughts on what we are trying to do?   We are currently doing some development where a lot of the steps and the variables are the same for maybe 20 jobs that we need to develop.   So we have a reason to want to have a common starting place (a template).