diff --git a/doomsday/libdeng2/include/de/core/system.h b/doomsday/libdeng2/include/de/core/system.h
index eea5a5a728..03c021c62b 100644
--- a/doomsday/libdeng2/include/de/core/system.h
+++ b/doomsday/libdeng2/include/de/core/system.h
@@ -50,7 +50,7 @@ class DENG2_PUBLIC System : DENG2_OBSERVES(Clock, TimeChange)
 public:
     System(Flags const &behavior = DefaultBehavior);
 
-    void setBehavior(Flags const &behavior);
+    void setBehavior(Flags const &behavior, FlagOp operation = SetFlags);
 
     Flags behavior() const;
 
diff --git a/doomsday/libdeng2/include/de/libdeng2.h b/doomsday/libdeng2/include/de/libdeng2.h
index cc67877139..dd17154427 100644
--- a/doomsday/libdeng2/include/de/libdeng2.h
+++ b/doomsday/libdeng2/include/de/libdeng2.h
@@ -392,6 +392,15 @@ enum FlagOp {
     ReplaceFlags = 2    ///< Specified flags become the new set of flags, replacing all previous flags.
 };
 
+template <typename FlagsType>
+void applyFlagOperation(FlagsType &flags, FlagsType const &newFlags, FlagOp operation) {
+    switch(operation) {
+    case SetFlags:     flags |= newFlags;  break;
+    case UnsetFlags:   flags &= ~newFlags; break;
+    case ReplaceFlags: flags = newFlags;   break;
+    }
+}
+
 /**
  * All serialization in all contexts use a common protocol version number.
  * Whenever anything changes in serialization, the protocol version needs to be
diff --git a/doomsday/libdeng2/include/de/widgets/widget.h b/doomsday/libdeng2/include/de/widgets/widget.h
index e99dcb3037..58b9d32473 100644
--- a/doomsday/libdeng2/include/de/widgets/widget.h
+++ b/doomsday/libdeng2/include/de/widgets/widget.h
@@ -77,8 +77,8 @@ class DENG2_PUBLIC Widget
 
     void show(bool doShow = true);
     inline void hide() { show(false); }
-    void enable(bool yes = true) { setBehavior(Disabled, !yes); }
-    void disable(bool yes = true) { setBehavior(Disabled, yes); }
+    void enable(bool yes = true) { setBehavior(Disabled, yes? UnsetFlags : SetFlags); }
+    void disable(bool yes = true) { setBehavior(Disabled, yes? SetFlags : UnsetFlags); }
 
     bool isHidden() const;
     inline bool isEnabled() const { return !behavior().testFlag(Disabled); }
@@ -90,7 +90,7 @@ class DENG2_PUBLIC Widget
      * @param behavior  Flags.
      * @param set       @c true to set, @c false to clear.
      */
-    void setBehavior(Behaviors behavior, bool set = true);
+    void setBehavior(Behaviors behavior, FlagOp operation = SetFlags);
 
     Behaviors behavior() const;
 
diff --git a/doomsday/libdeng2/src/core/system.cpp b/doomsday/libdeng2/src/core/system.cpp
index 46a25f207b..5e343a04ec 100644
--- a/doomsday/libdeng2/src/core/system.cpp
+++ b/doomsday/libdeng2/src/core/system.cpp
@@ -33,9 +33,9 @@ System::System(Flags const &behavior) : d(new Instance(this))
     d->behavior = behavior;
 }
 
-void System::setBehavior(Flags const &behavior)
+void System::setBehavior(Flags const &behavior, FlagOp operation)
 {
-    d->behavior = behavior;
+    applyFlagOperation(d->behavior, behavior, operation);
 }
 
 System::Flags System::behavior() const
diff --git a/doomsday/libdeng2/src/widgets/widget.cpp b/doomsday/libdeng2/src/widgets/widget.cpp
index 8da78aab9b..bd158998da 100644
--- a/doomsday/libdeng2/src/widgets/widget.cpp
+++ b/doomsday/libdeng2/src/widgets/widget.cpp
@@ -140,19 +140,12 @@ bool Widget::isHidden() const
 
 void Widget::show(bool doShow)
 {
-    setBehavior(Hidden, !doShow);
+    setBehavior(Hidden, doShow? UnsetFlags : SetFlags);
 }
 
-void Widget::setBehavior(Behaviors behavior, bool set)
+void Widget::setBehavior(Behaviors behavior, FlagOp operation)
 {
-    if(set)
-    {
-        d->behavior |= behavior;
-    }
-    else
-    {
-        d->behavior &= ~behavior;
-    }
+    applyFlagOperation(d->behavior, behavior, operation);
 }
 
 Widget::Behaviors Widget::behavior() const
diff --git a/doomsday/libshell/src/menuwidget.cpp b/doomsday/libshell/src/menuwidget.cpp
index d30c07db54..d890e5cfa9 100644
--- a/doomsday/libshell/src/menuwidget.cpp
+++ b/doomsday/libshell/src/menuwidget.cpp
@@ -115,7 +115,7 @@ MenuWidget::MenuWidget(Preset preset, String const &name)
     switch(preset)
     {
     case Popup:
-        setBehavior(HandleEventsOnlyWhenFocused, true);
+        setBehavior(HandleEventsOnlyWhenFocused);
         setClosable(true);
         d->cycleCursor = true;
         hide();