In the Beta 1A shipyard, when a design is made ready to name, and subsequently given a name the same as an existing design, it correctly warns you about overwriting etc and gives yes/no for continue. However if you press "no", you loose all the completed design work.
Suggest three buttons,
Yes - means go ahead and over write (tooltip on mouse over to say "overwrite")
No - means no, dont overwrite, I will give another name (tooltip "rename")
Clear - means forget it, clear all changes I'll start again (tooltip "clear design" )
Regards
Zy