Code review comment for lp:~jjed/unity/tooltips-redux

81 + SetIconUnderMouse((AbstractLauncherIcon::Ptr)nullptr);

Please pass an empty icon PTR to the function as it expects:
SetIconUnderMouse(AbstractLauncherIcon::Ptr());

245 + : show_tooltips_(false)
246 + , hovered_(false)
247 + , icon_(nullptr)
248 + , icon_clicked_(false)

This is pure style, but we use 2-spaces to indent initialization list, also you don't need to initialize the icon_ at all.

366 +class TooltipManager : public sigc::trackable

You don't need sigc::trackable, but you probably want this to be non-copyable instead.

371 + void SetHover(bool on_launcher);

What about a nux::Property<bool> for this?

258 + if (show_tooltips_) {

Please add a space after the if statements (so that the brace is on the new line)

539 + tm.SetIcon((AbstractLauncherIcon::Ptr)icon);

Pass to it an icon ptr: tm.SetIcon(AbstractLauncherIcon::Ptr(icon));