Separate the sidebar groups - local branches & workspace, remotes, tags, stashes, submodules - into tabs, similar to Xcode.

• Local: Keep "workspace" as a separate item at the top, and the hierarchical branch list below; may eventually contain workspaces
  • Indicate current branch
  • Filter can search entire name or last "path" component
  • Pull request and build status indicators
• Remotes: Each remote is listed, with its branches as sub-items
• Tags: Hierarchical list of tags
  • Solid or filled icon indicates regular vs lightweight tag
  • Certificate badge icon indicates signed tag
  • Maybe show date on the right for each tag
  • Rollover info icon has popover with more info
• Stashes: Chronological list of stashes
  • Changed file count indicator
  • Future feature: filter searches in file changes
• Submodules: Alphabetical list; does not affect the right side of the window

Each tab also has a filter field at the bottom, possibly also with an action popup and right-side icons for other filter options.

Add maybe in the future (to keep the initial scope contained):

• Search: move the current search bar to the sidebar
  • Option to search commit messages or changes
  • Regular expressions, fuzzy, or exact
  • Case sensitive
• File history: list changes to a selected/dragged file
  • Similar options as Search - regex etc
  • Selecting a result selects the commit and the file