Changelog

Calls mainWindow.AttachDevTools() in #if DEBUG so the built-in

element inspector, visual tree viewer, and layout visualizer are

available via F12 during development.

When a child's DesiredSize exceeds the arranged rect, ArrangeCore

may let the child render at its desired width, overflowing into the

adjacent pane. ClipToBounds on the parent Control doesn't reliably

clip in this scenario. Now explicitly sets Clip = RectangleGeometry

on each pane after arrange, guaranteeing content stays within its

allocated region.

The Border→SplitPanel→Border-host chain wasn't properly constraining

child content width. Rewrote as a Control subclass that directly

manages Pane1, Pane2, and the resize handle as visual/logical

children, with MeasureOverride and ArrangeOverride that measure each

child with its exact proportional width constraint and arrange at

exact rects. No intermediate containers to lose constraints.

ContentPresenter outside a ControlTemplate doesn't reliably present

Control content in Avalonia. Replaced with Border hosts that use

Child property directly.

Also fixed MeasureOverride: was returning availableSize which could

contain Infinity, causing the layout system to give zero size. Now

clamps infinite dimensions and measures each child with its

proportional share of space.

Code-only Border subclass with a custom inner Panel that arranges

two content panes and a draggable resize handle using ratio-based

math. Avoids the star-column minimum width issues that plague

Grid-based split implementations.

Properties: Ratio (pane2 fraction), MinRatio, MaxRatio, HandleSize,

Pane1, Pane2. Fires RatioChanged event on drag release for

persistence. During drag, uses an internal _dragRatio for live

feedback without updating the bound property on every pixel.

Replaces the inline resize logic pattern found in Tasks and Data

plugins with a single reusable component.