
Commit 91d8a32f25 let WindowClone forward the size-changed signal of the "real" window, disconnecting the signal handler when the clone is destroyed. In case the clone was destroyed due to the MetaWindowActor being closed, this results in a warning (gsignal.c:2392: instance `0x2a3fac0' has no handler with id `2955'). Handle the case where the original window is destroyed before its clone.