diff --git a/group.cpp b/group.cpp
index 79d4a2dd39..5f856e42d1 100644
--- a/group.cpp
+++ b/group.cpp
@@ -211,8 +211,15 @@ bool Client::belongToSameApplication( const Client* c1, const Client* c2, bool a
         ; // different apps
     else if( !sameAppWindowRoleMatch( c1, c2, active_hack ))
         ; // "different" apps
+    else if( c1->wmClientLeader() == c2->wmClientLeader()
+        && c1->wmClientLeader() != c1->window() // if WM_CLIENT_LEADER is not set, it returns window(),
+        && c2->wmClientLeader() != c2->window()) // don't use in this test then
+        same_app = true; // same client leader
+    else if( c1->group() == c2->group())
+        same_app = true; // same group
     else if( c1->pid() == 0 || c2->pid() == 0 )
         ; // old apps that don't have _NET_WM_PID, consider them different
+          // if they weren't found to match above
     else
         same_app = true; // looks like it's the same app
     return same_app;