function reposition (parentWindow) {
  // reposition all under this window
  for (let tab of tabManager.getAll(parentWindow)) {
    if (tab.id in views) {
      setBounds(views[tab.id], tab)
    }
  }
}
Prompts

NOTES
- Prompt views are created as-needed, and desroyed when not in use
- Prompt views are attached to individual BrowserView instances
- Prompt views are shown and hidden based on whether its owning BrowserView is visible