reduce relayouts

src/dlangui/platforms/windows/win32fonts.d

@@ -527,7 +527,7 @@ class Win32FontManager : FontManager {
     override ref FontRef getFont(int size, int weight, bool italic, FontFamily family, string face) {
 		//Log.i("getFont()");
 		FontDef * def = findFace(family, face);
-		Log.i("getFont() found face ", def.face, " by requested face ", face);
+		//Log.i("getFont() found face ", def.face, " by requested face ", face);
 		if (def !is null) {
 			int index = _activeFonts.find(size, weight, italic, def.family, def.face);
 			if (index >= 0)

src/dlangui/widgets/lists.d

@@ -529,6 +529,10 @@ class ListWidget : WidgetGroup, OnScrollHandler {
             pwidth -= m.left + m.right + p.left + p.right;
         if (parentHeight != SIZE_UNSPECIFIED)
             pheight -= m.top + m.bottom + p.top + p.bottom;
+
+        bool oldNeedLayout = _needLayout;
+        Visibility oldScrollbarVisibility = _scrollbar.visibility;
+
         _scrollbar.visibility = Visibility.Visible;
         _scrollbar.measure(pwidth, pheight);
 
@@ -606,6 +610,10 @@ class ListWidget : WidgetGroup, OnScrollHandler {
             }
         }
         measuredContent(parentWidth, parentHeight, sz.x + _sbsz.x, sz.y + _sbsz.y);
+        if (_scrollbar.visibility == oldScrollbarVisibility) {
+            _needLayout = oldNeedLayout;
+            _scrollbar.cancelLayout();
+        }
     }
 
 
@@ -715,6 +723,8 @@ class ListWidget : WidgetGroup, OnScrollHandler {
             makeSelectionVisible();
             _makeSelectionVisibleOnNextLayout = false;
         }
+        _needLayout = false;
+        _scrollbar.cancelLayout();
     }
 
     /// Draw widget at its position to buffer

src/dlangui/widgets/menu.d

@@ -779,6 +779,12 @@ class MainMenu : MenuWidgetBase {
             deactivate();
     }
 
+    /// request relayout of widget and its children
+    //override void requestLayout() {
+    //    Log.d("MainMenu.requestLayout is called");
+    //    super.requestLayout();
+    //}
+
     /// bring focus to main menu, if not yet activated
     void activate() {
         debug(DebugMenus) Log.d("activating main menu");

src/dlangui/widgets/widget.d

@@ -927,6 +927,10 @@ class Widget {
     }
 
 
+    void cancelLayout() {
+        _needLayout = false;
+    }
+
     /// set new timer to call onTimer() after specified interval (for recurred notifications, return true from onTimer)
     ulong setTimer(long intervalMillis) {
         return window.setTimer(this, intervalMillis);