Make the window-tabbing group of a window public via an XProperty.

atoms.cpp

@@ -123,6 +123,9 @@ Atoms::Atoms()
     atoms[n] = &kde_net_wm_opaque_region;
     names[n++] = (char*) "_KDE_NET_WM_OPAQUE_REGION";
 
+    atoms[n] = &kde_net_wm_tab_group;
+    names[n++] = (char*) "_KDE_NET_WM_TAB_GROUP";
+
     assert(n <= max);
 
     XInternAtoms(display(), names, n, false, atoms_return);

atoms.h

@@ -63,6 +63,7 @@ public:
     Atom kde_net_wm_block_compositing;
     Atom kde_net_wm_shadow;
     Atom kde_net_wm_opaque_region;
+    Atom kde_net_wm_tab_group;
 };
 
 

client.cpp

@@ -1834,6 +1834,14 @@ QString Client::caption(bool full) const
     return full ? cap_normal + cap_suffix : cap_normal;
 }
 
+void Client::setClientGroup(ClientGroup* group)
+{
+    client_group = group;
+    unsigned long data[1] = {(unsigned long)workspace()->indexOfClientGroup(group)};
+    XChangeProperty(display(), window(), atoms->kde_net_wm_tab_group, atoms->kde_net_wm_tab_group, 32,
+                    PropModeReplace, (unsigned char*)(data), 1);
+}
+
 void Client::dontMoveResize()
 {
     buttonDown = false;

client.h

@@ -818,11 +818,6 @@ inline Group* Client::group()
     return in_group;
 }
 
-inline void Client::setClientGroup(ClientGroup* group)
-{
-    client_group = group;
-}
-
 inline ClientGroup* Client::clientGroup() const
 {
     return client_group;

manage.cpp

@@ -319,7 +319,7 @@ bool Client::manage(Window w, bool isMapped)
     // Create client group if the window will have a decoration
     bool dontKeepInArea = false;
     if (!noBorder()) {
-        client_group = NULL;
+        setClientGroup(NULL);
         // Automatically add to previous groups on session restore
         if (session && session->clientGroupClient && session->clientGroupClient != this && session->clientGroupClient->clientGroup())
             session->clientGroupClient->clientGroup()->add(this, -1, true);
@@ -349,7 +349,7 @@ bool Client::manage(Window w, bool isMapped)
             }
         }
         if (!client_group)
-            client_group = new ClientGroup(this);
+            setClientGroup(new ClientGroup(this));
     }
 
     updateDecoration(false);   // Also gravitates

workspace.cpp

@@ -2098,6 +2098,21 @@ void Workspace::moveItemToClientGroup(ClientGroup* oldGroup, int oldIndex,
     group->add(c, index, true);
 }
 
+void Workspace::removeClientGroup(ClientGroup* group)
+{
+    int index = clientGroups.indexOf(group);
+    if (index == -1) {
+        return;
+    }
+
+    clientGroups.removeAt(index);
+    for (; index < clientGroups.size(); index++) {
+        foreach (Client *c, clientGroups.at(index)->clients()) {
+            c->setClientGroup(c->clientGroup());
+        }
+    }
+}
+
 // To accept "mainwindow#1" to "mainwindow#2"
 static QByteArray truncatedWindowRole(QByteArray a)
 {

workspace.h

@@ -1225,11 +1225,6 @@ inline void Workspace::addClientGroup(ClientGroup* group)
     clientGroups.append(group);
 }
 
-inline void Workspace::removeClientGroup(ClientGroup* group)
-{
-    clientGroups.removeAll(group);
-}
-
 } // namespace
 
 #endif