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PanedWindow

PanedWindow is a resizable split container that arranges child panes with draggable separators.

It wraps bs.Panedwindow and is used to build layouts like:

  • sidebar + content

  • navigator + editor + inspector

  • vertically stacked regions with adjustable heights

Quick start

import bootstack as bs

app = bs.App()

pw = bs.PanedWindow(app, orient="horizontal")
pw.pack(fill="both", expand=True)

sidebar = bs.Frame(pw, padding=12, width=220)
content = bs.Frame(pw, padding=12)

pw.add(sidebar, weight=0)
pw.add(content, weight=1)

bs.Label(sidebar, text="Sidebar").pack(anchor="w")
bs.Label(content, text="Content").pack(anchor="w")

app.mainloop()

When to use

Use PanedWindow when:

  • users benefit from adjustable regions

  • your app has a "workbench" layout (nav/editor/inspector)

Consider a different control when:

  • the layout should be fixed -- use Frame containers

  • resizing regions would add complexity without benefit

Appearance

A paned layout works well when:

  • panes have different importance (content gets most space)

  • users may want to expand/collapse a region temporarily

  • window resizing should feel responsive

Design System

For theming details and color tokens, see Design System.

Examples & patterns

Core concepts

Panes

Each child added to a paned window is a pane. You can assign weights (if supported) to influence how extra space is distributed.

Sashes

The draggable separators between panes are called sashes. Users drag sashes to resize panes.

orient

bs.PanedWindow(app, orient="horizontal")  # left/right
bs.PanedWindow(app, orient="vertical")    # top/bottom

Adding panes: add(...)

pw.add(frame)
pw.add(frame, weight=1)

Removing panes

Use the ttk panedwindow API (varies by implementation/version).

UX guidance

  • Don't overuse panes -- 2 (or 3) is usually enough.

  • Provide sensible default sizes.

  • Consider minimum sizes for panes that contain dense UI (lists, trees, inspectors).

Behavior

  • Users drag the sash to resize adjacent panes.

  • Panes can be sized by the program (e.g., setting widths/heights + disabling propagation on child frames).

  • If you need collapsible panes, pair with explicit show/hide controls and remember prior sash positions.

Additional resources

  • Frame -- typical pane content container

  • Separator -- lightweight alternative when panes are fixed

  • ScrollView -- scroll content within a pane

Framework concepts

API reference