To hide fields:
1. Click the gear icon on the lower right-hand corner of the sidebar.
2. Select Options from the pop-up menu
3. A new window will pop-up, from General navigate to Advanced settings.
4. Click the Configure button beside Configure Module Fields.
5. A smaller window will pop-up.
6. From dropdown menu, select which module to modify.
7. From Enabled Fields list, select which fields to hide.
8. Don't forget to click Save.
Same process applies when unhiding fields in the Collabspot sidebar. Just click the field under Disabled Fields list and don't forget to click Save.
NOTE: Refresh Gmail to update to the latest changes.