name wxThreadEvent and YieldFor in wxProgressDialog and in thread overview; update the sample code to use new event macros; minor other changes

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@59002 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/event.h

@@ -147,6 +147,7 @@ public:
 
     /**
         Returns a generic category for this event.
+        wxEvent implementation returns @c wxEVT_CATEGORY_UI by default.
 
         This function is used to selectively process events in wxEventLoopBase::YieldFor.
     */
@@ -2030,6 +2031,11 @@ public:
     This event class contains information about command events, which originate
     from a variety of simple controls.
 
+    Note that wxCommandEvents and wxCommandEvent-derived event classes by default
+    and unlike other wxEvent-derived classes propagate upward from the source
+    window (the window which emits the event) up to the first parent which processes
+    the event. Be sure to read @ref overview_events_propagation.
+
     More complex controls, such as wxTreeCtrl, have separate command event classes.
 
     @beginEventTable{wxCommandEvent}
@@ -2534,6 +2540,12 @@ public:
     This class adds some simple functionalities to wxCommandEvent coinceived
     for inter-threads communications.
 
+    This event is not natively emitted by any control/class: this is just
+    an helper class for the user.
+    Its most important feature is the GetEventCategory() implementation which
+    allows thread events to @b NOT be processed by wxEventLoopBase::YieldFor calls
+    (unless the @c wxEVT_CATEGORY_THREAD is specified - which is never in wx code).
+
     @library{wxcore}
     @category{events}