diff --git a/docs/changes.txt b/docs/changes.txt
index f4867d6ac6..73471219dd 100644
--- a/docs/changes.txt
+++ b/docs/changes.txt
@@ -71,6 +71,10 @@ All:
 
 - Make wxList and wxVector iterators conform to input iterator requirements.
 
+wxMSW:
+
+- Fix hang after clearing wxTAB_TRAVERSAL style on a window with children.
+
 
 3.1.1: (released 2018-02-19)
 ----------------------------
diff --git a/src/msw/window.cpp b/src/msw/window.cpp
index 0082cef587..ca8fccb9da 100644
--- a/src/msw/window.cpp
+++ b/src/msw/window.cpp
@@ -1409,7 +1409,14 @@ void wxWindowMSW::MSWUpdateStyle(long flagsOld, long exflagsOld)
                                       WS_SYSMENU) ) != 0;
     }
 
-    // and the extended style
+    // There is one extra complication with the extended style: we must never
+    // reset WS_EX_CONTROLPARENT because it may break the invariant that the
+    // parent of any window with this style bit set has it as well. We enforce
+    // this invariant elsewhere and must not clear it here to avoid the fatal
+    // problems (hangs) which happen if we break it, so ensure it is preserved.
+    if ( exstyleOld & WS_EX_CONTROLPARENT )
+        exstyle |= WS_EX_CONTROLPARENT;
+
     wxMSWWinExStyleUpdater updateExStyle(GetHwnd());
     if ( updateExStyle.TurnOff(exstyleOld).TurnOn(exstyle).Apply() )
     {