v0.4.0

Added

• ScrollBar arrow buttons now behave like real push buttons. Clicking one
  sinks it — a single dark top/left shadow line, no highlight, the arrow glyph
  nudged 1px down-right — and holding it auto-repeats the line-step scroll at
  a keyboard-style cadence (a ~300ms initial delay, then every 50ms) for as long
  as the button stays pressed with the pointer over it; sliding off pauses the
  repeat and pops the button back out, sliding back resumes it. (#41)
• EventCtx::request_tick asks the runtime to deliver another Event::Tick
  without any ancestor having to forward the request — the push counterpart to
  Widget::wants_ticks. Like request_paint, it rides the shared EventCtx
  straight back to the runtime, so a widget buried under custom wrapper widgets
  can drive a transient animation on its own. It is one-shot: a widget that
  needs a stream re-requests on each tick. The scrollbar's hold-to-repeat uses
  it, which is why it works even inside a wrapper that doesn't forward
  wants_ticks (such as the filer example's FileBrowser). (#41)
• FocusLabel is a caption that carries a keyboard mnemonic and moves focus to
  the field beside it. Mark the accelerator with & exactly like a menu label
  ("Last &name:" underlines the n and binds Alt+N); pressing it
  transfers focus to the next focusable widget added to the same parent — the
  classic "buddy label" convention. The accelerator reaches the label even while
  a sibling holds focus, via a new EventCtx::request_focus_next request that
  Container, Column, and Row resolve. See the new focus_form example.
  (#39)
• MockBackend::render_framed now paints the window background pattern behind
  the content for regular (resizable / fixed) windows, matching the live
  backend's main surface; dialogs stay plain, as they do on screen. The pattern
  defaults to the live default (a superlight forward-diagonal hatch) and is
  overridable with the new MockBackend::with_background_pattern. (#38)
• List gained optional multi-selection, off by default so existing
  single-selection lists are unchanged. Enable it with List::with_multi_select
  / set_multi_select: Ctrl/Cmd+click toggles a row, Shift+click and Shift+Arrow
  select a contiguous range, and selected_indices / set_selected_indices read
  and set the whole set. A plain press on an already-selected row defers
  collapsing the selection until release, so a wrapper can drag the whole group
  out — the picker and filer examples now do. To carry the click modifiers,
  Event::PointerDown and Event::PointerUp now include a modifiers field.
  (#37)
• Widgets can request the mouse-pointer shape while handling a pointer event
  via EventCtx::set_cursor, choosing from the new Cursor enum (arrow, hand,
  I-beam, resize handles, …). The runtime applies it after each move on both
  backends (wp_cursor_shape on Wayland, CursorIcon on X11/Windows/macOS) and
  falls back to the arrow when no widget asks. TextInput / TextEditor show
  the I-beam over their text; every other widget keeps the default arrow. (#42)
• WindowConfig::min_size sets the smallest inner size a resizable window may
  be dragged to (in logical pixels). The window manager enforces the bound, so
  layouts never see sizes below it. (#36)

Fixed

• On Wayland, the mouse pointer could keep a stale shape when entering a window
  or surface. Wayland leaves the pointer image undefined on wl_pointer.enter
  and makes the client set it, but the runtime deduplicated against the last
  shape it had shown and so skipped re-establishing the arrow on entry. It now
  forces the cursor shape on every enter (plain motion still dedups). (#42)
• On X11, dragging a ScrollBar / Slider thumb (or any captured press) no
  longer stops the moment the pointer leaves the window. winit reports the
  cursor crossing the window edge as a CursorLeft even while X11's implicit
  pointer grab keeps motion flowing during a held button, so the runtime took it
  for a real leave and ended the drag. It now ignores that leave while a button
  is held and a widget is capturing the pointer, so the drag keeps tracking
  up/down motion until release — matching the Wayland backend, whose compositor
  sends no leave during its implicit grab. (#40)