In the site folder I get bullet points for each page rather than the triangle which opens and closes the page.
If you are referring to the Page/Site sidebar on the left of your screen then the Black Bullet signifies a page that has content that has changed and hasn’t yet been published.
The different views in that sidebar can be set using the Gear icon down at the bottom of the sidebar. (Show Pages, Show Items, Show Links and Show Alt Text. You can also enable Show File Sizes with any of the previous 4)
Clicking on the sidebar header (which toggles between Site and Page) gives a quick way of changing views.
Normally I use ‘Show Pages’ then when I Toggle the header I get the item view - which shows all items on the page I am working on.
If I have misunderstood your question feel free to elaborate.