Miller Columns

Span Finder’s signature navigation mode — the feature most users install the app for. If you have ever missed macOS Finder’s column view on Windows, this is the page for you.

Table of contents

  1. What is it?
  2. When to use it
  3. How it works
    1. Opening a folder
    2. Keyboard navigation
    3. Column widths
    4. Auto-scroll
  4. Miller Columns vs. traditional tree view
  5. Settings
  6. Tips & gotchas
  7. See also

What is it?

Miller Columns is a hierarchical file browser that shows every level of a folder path at the same time, laid out left to right. Click a folder in column 1 and its contents appear in column 2. Click a subfolder in column 2 and column 3 opens. You never lose track of where you are, where you came from, or what siblings exist at each level.

Traditional Windows Explorer replaces the current view every time you enter a folder. You have to mentally stack breadcrumbs in your head and click Back to undo a wrong turn. Miller Columns eliminates that problem — the entire path is visible on screen, all the time.

Tip: Press Ctrl + 1 at any time to switch back to Miller Columns from another view mode.

When to use it

Miller Columns shines when you are:

  • Exploring an unfamiliar folder tree — you can see siblings at every level without backtracking
  • Moving or copying across deep hierarchies — drag between columns without losing context
  • Auditing project structures — see at a glance how folders are organized
  • Drilling into monorepos or source trees — src → Span → Services → .cs file, all visible at once

If you mostly work in a flat directory, switch to Details (Ctrl + 2) or Icons (Ctrl + 4) instead.

How it works

Opening a folder

Click a folder. A new column slides in to the right showing its contents. The previously active column stays visible — its selection is still highlighted so you know the full path.

Double-click behavior is configurable in Settings. By default Miller Columns uses single-click to navigate (like macOS Finder), but you can set it to double-click if you prefer Windows Explorer semantics.

Keyboard navigation

Miller Columns is built for the keyboard. Every common action has a shortcut:

Key Action
Left / Right Move between columns
Up / Down Move within the current column
Enter Open folder / launch file
Backspace Go up one column (back toward the root)
Home / End Jump to first / last item in the column
A–Z, 0–9 Type-ahead search — starts filtering the column as you type (800 ms buffer)
Space Open Quick Look preview (if enabled in Settings)

Because every column is independently focusable, you can navigate with arrows alone — no mouse required.

Column widths

Drag any column separator to resize. Three handy defaults cover most situations:

Action Shortcut / Gesture
Equalize all columns to the same width Ctrl + Shift + =
Auto-fit the active column to its longest item Ctrl + Shift + -
Auto-fit a single column to its content Double-click its right edge
Apply the current column’s width to every column Hold Ctrl while dragging the separator

Column widths are saved per session and restored on the next launch.

Auto-scroll

As you drill deeper, Span Finder smoothly scrolls horizontally to keep the active column in view. You never have to manually pan.

Miller Columns vs. traditional tree view

  Tree view (Explorer left pane) Miller Columns
Shows siblings at every level Only for the path you expanded Yes, always
Wasted vertical space on deep trees High — long indented lines None — horizontal layout
Click to change level Requires expand/collapse discipline Single click moves laterally
Keyboard navigation Up/Down only Arrows in two dimensions
Good for wide folders No — vertical scroll mess Yes — column width is adjustable

A tree view forces you to think of folders as a vertical outline. Miller Columns treats the hierarchy as a conveyor belt that slides sideways — most people who try it stop going back.

Settings

Open Settings with Ctrl + , and look under Appearance and Navigation for Miller-specific options:

  • Click behavior — Single click (default) vs. double click to enter a folder
  • Thumbnails — Show/hide image thumbnails in Miller cells
  • Checkboxes — Enable checkbox selection mode
  • Row density — Compact / Comfortable / Spacious (paired with 6-step font/icon size)
  • Hidden files — Show or hide dotfiles and system-hidden items
  • File extensions — Toggle extension visibility (also Ctrl + Shift + H)

Tips & gotchas

Tip: Use Backspace instead of Alt + Left when you want to go one level up. Alt+Left goes back in history, which may not be the parent folder if you navigated laterally.

Tip: When comparing two folders at the same depth, open Split View (Ctrl + E) and put Miller Columns on both sides.

Gotcha: Type-ahead search has an 800 ms buffer. If you pause, the next keypress starts a new search. This matches Finder and Explorer behavior.

Gotcha: Very wide columns can push the active column off-screen on small displays. Use Ctrl + Shift + - to auto-fit everything at once.

See also