Please consider adding a tabs counter in somewhere in a visible place, for example:

1. Before X button in Menu bar.
2. Or somewhere in Status bar.
3. Or any other better visible place.

This is a very convenient improvement for people who work on a large number of tabs, and sometimes by mistake we close some tab/tabs. With tabs counter we can easy control if our sets of tabs is complete.

Format for tabs counter can be just Number or Number/Number (for two views), or more obvious like Tabs: Number or Tabs: Number/Number in Status bar. This can also be optional for people who don't need it (some checkbox in Preferences). In detail, this can be done in different ways, it is more important to accept this future.