saving the open edited files is not always useful if u will just test something. auto backup and a copy for compiling is good.
its better if the ide use the files that are not open in the editor and that one (the content) are open in the editor but not saved, for compiling.
vb6 had optional a requester that is was possible to save before start the app but save was not required, so it was possible to open / edit a project , run it,
and if you dislike your changes, just close it and reopen the project and you got the original saved state.
load/save of project source code should be controlled by the user.