Merge pull request #4977 from Diax170/drawer-state

Add CSS selector for expanded drawers

man/waybar.5.scd.in

@@ -375,6 +375,8 @@ A group may hide all but one element, showing them only on mouse hover. In order
 	Defines the direction of the transition animation. If true, the hidden elements will slide from left to right. If false, they will slide from right to left.
 	When the bar is vertical, it reads as top-to-bottom.
 
+Group drawers are also given the `.expanded` CSS class when they are expanded.
+
 ```
 "group/power": {
     "orientation": "inherit",

src/group.cpp

@@ -96,11 +96,13 @@ Group::Group(const std::string& name, const std::string& id, const Json::Value&
 void Group::show_group() {
   box.set_state_flags(Gtk::StateFlags::STATE_FLAG_PRELIGHT);
   revealer.set_reveal_child(true);
+  box.get_style_context()->add_class("expanded");
 }
 
 void Group::hide_group() {
   box.unset_state_flags(Gtk::StateFlags::STATE_FLAG_PRELIGHT);
   revealer.set_reveal_child(false);
+  box.get_style_context()->remove_class("expanded");
 }
 
 bool Group::handleMouseEnter(GdkEventCrossing* const& e) {