v0.1.0-preview.2

Changed

• Xtreme.Components.Docking: the docking guides are redrawn. Each button is a small window
  picture with the landing part filled in, the buttons of a compass share one raised cross-shaped
  plate, the document compass shows the document at its center, and the inner and outer buttons
  picture the difference between the two bands. Colors come from the new optional
  XcDockGuide<Role>Brush tokens; the landing wash is a lighter tint that stays visible over a
  blue pane.
• Xtreme.Components.Docking: floating windows are placed. A first float opens over the pane at
  its docked size (capped at 80% of the monitor), a drag float opens under the pointer with the
  grab point kept, a pane that floated before reopens at its last size (and, from the menu, its
  last position), and every new window is fitted onto a connected monitor. A docked pane's last
  floating bounds are saved in the layout. On Windows the screen mapping uses the real client area
  instead of an estimated title bar.

Fixed

• Xtreme.Components.Docking: a canceled pointer or a lost pointer capture no longer commits the
  drag (it could float or move the pane); it cancels. Escape cancels an in-host drag.
• Xtreme.Components.Docking: a drop whose placement throws, a window that fails to construct, the
  host unloading mid-drag, or a floating pane closing during its drag-back no longer leaves guides
  on screen, a pane stranded with no window, or a drag armed that blocks every later drag.
• Win32DockPlatformServices: a throwing drag callback no longer silences the tracker, a dead
  window stops its tracker, and a disposed tracker forgets an in-progress carry so a pooled window
  can't inherit it.