diff --git a/clientgui/AsyncRPC.cpp b/clientgui/AsyncRPC.cpp
index 04633d5960..047fc7d3a7 100755
--- a/clientgui/AsyncRPC.cpp
+++ b/clientgui/AsyncRPC.cpp
@@ -736,6 +736,15 @@ void CMainDocument::HandleCompletedRPC() {
 #endif  // ! __WXMSW__       // Deadlocks on Windows
     }
 
+    // We must call ProcessEvent() rather than AddPendingEvent() here to 
+    // guarantee integrity of data when other events are handled (such as 
+    // Abort, Suspend/Resume, Show Graphics, Update, Detach, Reset, No 
+    // New Work, etc.)  Otherwise, if one of those events is pending it 
+    // might be processed first, and the data in the selected rows may not 
+    // match the data which the user selected if any rows were added or 
+    // deleted due to the RPC.  
+    // The refresh event called here adjusts the selections to fix any 
+    // such mismatch before other pending events are processed.  
     if ( (crr_event) && (crr_event != (wxEvent*)-1) ) {
         if (!retval) {
             if (crr_eventHandler) {
diff --git a/clientgui/BOINCGUIApp.cpp b/clientgui/BOINCGUIApp.cpp
index fa47d58d79..6b47cb674c 100644
--- a/clientgui/BOINCGUIApp.cpp
+++ b/clientgui/BOINCGUIApp.cpp
@@ -207,6 +207,10 @@ bool CBOINCGUIApp::OnInit() {
 #if wxCHECK_VERSION(2,8,0)
 // In wxMac-2.8.7, default wxListCtrl::RefreshItem() does not work
 // so use traditional generic implementation.
+// This has been fixed in wxMac-2.8.8, but the Mac native implementation:
+//  - takes 3 times the CPU time as the Mac generic version.
+//  - seems to always redraw entire control even if asked to refresh only one row.
+//  - causes major flicker of progress bars, (probably due to full redraws.)
     wxSystemOptions::SetOption(wxT("mac.listctrl.always_use_generic"), 1);
 #endif
 	
diff --git a/clientgui/BOINCListCtrl.h b/clientgui/BOINCListCtrl.h
index 84b5926428..b4578b13d4 100644
--- a/clientgui/BOINCListCtrl.h
+++ b/clientgui/BOINCListCtrl.h
@@ -32,6 +32,12 @@
 #define LISTCTRL_BASE wxListCtrl
 #include "wx/listctrl.h"
 #else
+// In wxMac-2.8.7, default wxListCtrl::RefreshItem() does not work
+// so use traditional generic implementation.
+// This has been fixed in wxMac-2.8.8, but the Mac native implementation:
+//  - takes 3 times the CPU time as the Mac generic version.
+//  - seems to always redraw entire control even if asked to refresh only one row.
+//  - causes major flicker of progress bars, (probably due to full redraws.)
 #define LISTCTRL_BASE wxGenericListCtrl
 #include "wx/generic/listctrl.h"
 #endif