This is a common request -- we have a change request filed to add an option for tagging to behave this way.
The reason we have held off on implementing it is we do not have a terrific solution for the person who has that option enabled, but then he wants to jump to a tag with the same name in another project. While not the common case, there will be times when you need to do this, so there must be a convenient way to get the old behavior.
It is too inconvenient to toggle the option on/off as needed. It is too demanding to add a new command or a new keyboard shortcut to show all choices. Keep in mind, we would have to solve this for both Ctrl+Dot and Ctrl+Slash (references).
There is one proposed solution, which is to prompt showing all the available symbol matches like we do now, but float the matches in the current project up to the top of the list. Then most of the time you would just hit "enter" to jump to the tag in your current project. It does mean that you will be prompted even if there is exactly one symbol in your current projects (and others in other projects), instead of going directly to the tag.