guard against nullptr

[wxWidgets.git] / src / msw / treectrl.cpp

diff --git a/src/msw/treectrl.cpp b/src/msw/treectrl.cpp
index 4fd9657d16d5814f2ef7d31fa24819e95cb36230..d7aebb80d67ca48116891e7f3a2fb93f8d7c7f73 100644 (file)
--- a/src/msw/treectrl.cpp
+++ b/src/msw/treectrl.cpp
@@ -42,6 +42,7 @@
 
 #include "wx/imaglist.h"
 #include "wx/msw/dragimag.h"
+#include "wx/msw/uxtheme.h"
 
 // macros to hide the cast ugliness
 // --------------------------------
@@ -76,7 +77,7 @@ typedef struct tagNMTVITEMCHANGE
 // The vista tree control includes some new code that originally broke the
 // multi-selection tree, causing seemingly spurious item selection state changes
 // during Shift or Ctrl-click item selection. (To witness the original broken
-// behavior, simply make IsLocked() below always return false). This problem was
+// behaviour, simply make IsLocked() below always return false). This problem was
 // solved by using the following class to 'unlock' an item's selection state.
 
 class TreeItemUnlocker
@@ -741,6 +742,20 @@ bool wxTreeCtrl::Create(wxWindow *parent,
 
     wxSetCCUnicodeFormat(GetHwnd());
 
+    if ( m_windowStyle & wxTR_TWIST_BUTTONS )
+    {
+        // Under Vista and later Explorer uses rotating ("twist") buttons
+        // instead of the default "+/-" ones so apply its theme to the tree
+        // control to implement this style.
+        if ( wxGetWinVersion() >= wxWinVersion_Vista )
+        {
+            if ( wxUxThemeEngine *theme = wxUxThemeEngine::GetIfActive() )
+            {
+                theme->SetWindowTheme(GetHwnd(), L"EXPLORER", NULL);
+            }
+        }
+    }
+
     return true;
 }
 
@@ -3356,7 +3371,7 @@ bool wxTreeCtrl::MSWOnNotify(int idCtrl, WXLPARAM lParam, WXLPARAM *result)
         // the wrong items are deselected.
 
         // Fortunately, Vista provides a new notification, TVN_ITEMCHANGING
-        // that can be used to regulate this incorrect behavior.  The
+        // that can be used to regulate this incorrect behaviour.  The
         // following messages will allow only the unlocked item's selection
         // state to change