Proposal

Storage details is meant to show over all storage size, Used storage and unused storage space. Here a user can see these details and decide how to utilize their storage capacity.

Suggestion

I have edited a screenshot of the OI filemanager user interface and edited it to further explain this suggestion.

• Before
  

• After
  

Benefits

Storage details are shown, used and unused space details are also displayed.
The red part of the progress bar indicates used up storage and the white indicate unused storage space.
When a particular storage is nearly filled up to an extent which is not healthy. The Used storgae details is displayed in red as you can see on my screenshot for memory card.
This would be a welcome development and a useful additon to the OI file manager for all the reasons above. I want to urge the devs to bring this feature to the app soon.